# Visualization

We use the standard convention for referencing the matplotlib API:

In [1]: import matplotlib.pyplot as plt

In [2]: plt.close('all')

We provide the basics in pandas to easily create decent looking plots. See the ecosystem (opens new window) section for visualization libraries that go beyond the basics documented here.

Note

All calls to np.random are seeded with 123456.

# Basic plotting: plot

We will demonstrate the basics, see the cookbook for some advanced strategies.

The plot method on Series and DataFrame is just a simple wrapper around plt.plot() (opens new window):

In [3]: ts = pd.Series(np.random.randn(1000),
   ...:                index=pd.date_range('1/1/2000', periods=1000))
   ...: 

In [4]: ts = ts.cumsum()

In [5]: ts.plot()
Out[5]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d8c0ac50>

series_plot_basic

If the index consists of dates, it calls gcf().autofmt_xdate() (opens new window) to try to format the x-axis nicely as per above.

On DataFrame, plot() (opens new window) is a convenience to plot all of the columns with labels:

In [6]: df = pd.DataFrame(np.random.randn(1000, 4),
   ...:                   index=ts.index, columns=list('ABCD'))
   ...: 

In [7]: df = df.cumsum()

In [8]: plt.figure();

In [9]: df.plot();

frame_plot_basic

You can plot one column versus another using the x and y keywords in plot() (opens new window):

In [10]: df3 = pd.DataFrame(np.random.randn(1000, 2), columns=['B', 'C']).cumsum()

In [11]: df3['A'] = pd.Series(list(range(len(df))))

In [12]: df3.plot(x='A', y='B')
Out[12]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d97c1668>

df_plot_xy

Note

For more formatting and styling options, see formatting below.

# Other plots

Plotting methods allow for a handful of plot styles other than the default line plot. These methods can be provided as the kind keyword argument to plot() (opens new window), and include:

For example, a bar plot can be created the following way:

In [13]: plt.figure();

In [14]: df.iloc[5].plot(kind='bar');

bar_plot_ex

You can also create these other plots using the methods DataFrame.plot. instead of providing the kind keyword argument. This makes it easier to discover plot methods and the specific arguments they use:

In [15]: df = pd.DataFrame()

In [16]: df.plot.<TAB>  # noqa: E225, E999
df.plot.area     df.plot.barh     df.plot.density  df.plot.hist     df.plot.line     df.plot.scatter
df.plot.bar      df.plot.box      df.plot.hexbin   df.plot.kde      df.plot.pie

In addition to these kind s, there are the DataFrame.hist(), and DataFrame.boxplot() methods, which use a separate interface.

Finally, there are several plotting functions in pandas.plotting that take a Series (opens new window) or DataFrame (opens new window) as an argument. These include:

Plots may also be adorned with errorbars or tables.

# Bar plots

For labeled, non-time series data, you may wish to produce a bar plot:

In [17]: plt.figure();

In [18]: df.iloc[5].plot.bar()
Out[18]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da446a90>

In [19]: plt.axhline(0, color='k');

bar_plot_ex

Calling a DataFrame’s plot.bar() (opens new window) method produces a multiple bar plot:

In [20]: df2 = pd.DataFrame(np.random.rand(10, 4), columns=['a', 'b', 'c', 'd'])

In [21]: df2.plot.bar();

bar_plot_multi_ex

To produce a stacked bar plot, pass stacked=True:

In [22]: df2.plot.bar(stacked=True);

bar_plot_stacked_ex

To get horizontal bar plots, use the barh method:

In [23]: df2.plot.barh(stacked=True);

barh_plot_stacked_ex

# Histograms

Histograms can be drawn by using the DataFrame.plot.hist() (opens new window) and Series.plot.hist() (opens new window) methods.

In [24]: df4 = pd.DataFrame({'a': np.random.randn(1000) + 1, 'b': np.random.randn(1000),
   ....:                     'c': np.random.randn(1000) - 1}, columns=['a', 'b', 'c'])
   ....: 

In [25]: plt.figure();

In [26]: df4.plot.hist(alpha=0.5)
Out[26]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da345e48>

hist_new

A histogram can be stacked using stacked=True. Bin size can be changed using the bins keyword.

In [27]: plt.figure();

In [28]: df4.plot.hist(stacked=True, bins=20)
Out[28]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da30b9b0>

hist_new_stacked

You can pass other keywords supported by matplotlib hist. For example, horizontal and cumulative histograms can be drawn by orientation='horizontal' and cumulative=True.

In [29]: plt.figure();

In [30]: df4['a'].plot.hist(orientation='horizontal', cumulative=True)
Out[30]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da69fd68>

hist_new_kwargs

See the hist (opens new window) method and the matplotlib hist documentation (opens new window) for more.

The existing interface DataFrame.hist to plot histogram still can be used.

In [31]: plt.figure();

In [32]: df['A'].diff().hist()
Out[32]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65dac9d240>

hist_plot_ex

DataFrame.hist() (opens new window) plots the histograms of the columns on multiple subplots:

In [33]: plt.figure()
Out[33]: <Figure size 640x480 with 0 Axes>

In [34]: df.diff().hist(color='k', alpha=0.5, bins=50)
Out[34]: 
array([[<matplotlib.axes._subplots.AxesSubplot object at 0x7f6601550cc0>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f66079a9400>],
       [<matplotlib.axes._subplots.AxesSubplot object at 0x7f65f87ac828>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f6604bd6b70>]],
      dtype=object)

frame_hist_ex

The by keyword can be specified to plot grouped histograms:

In [35]: data = pd.Series(np.random.randn(1000))

In [36]: data.hist(by=np.random.randint(0, 4, 1000), figsize=(6, 4))
Out[36]: 
array([[<matplotlib.axes._subplots.AxesSubplot object at 0x7f6601550ef0>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9b82438>],
       [<matplotlib.axes._subplots.AxesSubplot object at 0x7f65dc30ba58>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65f63c2320>]],
      dtype=object)

grouped_hist

# Box plots

Boxplot can be drawn calling Series.plot.box() (opens new window) and DataFrame.plot.box() (opens new window), or DataFrame.boxplot() (opens new window) to visualize the distribution of values within each column.

For instance, here is a boxplot representing five trials of 10 observations of a uniform random variable on [0,1).

In [37]: df = pd.DataFrame(np.random.rand(10, 5), columns=['A', 'B', 'C', 'D', 'E'])

In [38]: df.plot.box()
Out[38]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da17f898>

box_plot_new

Boxplot can be colorized by passing color keyword. You can pass a dict whose keys are boxes, whiskers, medians and caps. If some keys are missing in the dict, default colors are used for the corresponding artists. Also, boxplot has sym keyword to specify fliers style.

When you pass other type of arguments via color keyword, it will be directly passed to matplotlib for all the boxes, whiskers, medians and caps colorization.

The colors are applied to every boxes to be drawn. If you want more complicated colorization, you can get each drawn artists by passing return_type.

In [39]: color = {'boxes': 'DarkGreen', 'whiskers': 'DarkOrange',
   ....:          'medians': 'DarkBlue', 'caps': 'Gray'}
   ....: 

In [40]: df.plot.box(color=color, sym='r+')
Out[40]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da880b00>

box_new_colorize

Also, you can pass other keywords supported by matplotlib boxplot. For example, horizontal and custom-positioned boxplot can be drawn by vert=False and positions keywords.

In [41]: df.plot.box(vert=False, positions=[1, 4, 5, 6, 8])
Out[41]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65db18ffd0>

box_new_kwargs

See the boxplot (opens new window) method and the matplotlib boxplot documentation (opens new window) for more.

The existing interface DataFrame.boxplot to plot boxplot still can be used.

In [42]: df = pd.DataFrame(np.random.rand(10, 5))

In [43]: plt.figure();

In [44]: bp = df.boxplot()

box_plot_ex

You can create a stratified boxplot using the by keyword argument to create groupings. For instance,

In [45]: df = pd.DataFrame(np.random.rand(10, 2), columns=['Col1', 'Col2'])

In [46]: df['X'] = pd.Series(['A', 'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', 'B'])

In [47]: plt.figure();

In [48]: bp = df.boxplot(by='X')

box_plot_ex2

You can also pass a subset of columns to plot, as well as group by multiple columns:

In [49]: df = pd.DataFrame(np.random.rand(10, 3), columns=['Col1', 'Col2', 'Col3'])

In [50]: df['X'] = pd.Series(['A', 'A', 'A', 'A', 'A', 'B', 'B', 'B', 'B', 'B'])

In [51]: df['Y'] = pd.Series(['A', 'B', 'A', 'B', 'A', 'B', 'A', 'B', 'A', 'B'])

In [52]: plt.figure();

In [53]: bp = df.boxplot(column=['Col1', 'Col2'], by=['X', 'Y'])

box_plot_ex3

Warning

The default changed from 'dict' to 'axes' in version 0.19.0.

In boxplot, the return type can be controlled by the return_type, keyword. The valid choices are {"axes", "dict", "both", None}. Faceting, created by DataFrame.boxplot with the by keyword, will affect the output type as well:

return_type= Faceted Output type
None No axes
None Yes 2-D ndarray of axes
'axes' No axes
'axes' Yes Series of axes
'dict' No dict of artists
'dict' Yes Series of dicts of artists
'both' No namedtuple
'both' Yes Series of namedtuples

Groupby.boxplot always returns a Series of return_type.

In [54]: np.random.seed(1234)

In [55]: df_box = pd.DataFrame(np.random.randn(50, 2))

In [56]: df_box['g'] = np.random.choice(['A', 'B'], size=50)

In [57]: df_box.loc[df_box['g'] == 'B', 1] += 3

In [58]: bp = df_box.boxplot(by='g')

boxplot_groupby

The subplots above are split by the numeric columns first, then the value of the g column. Below the subplots are first split by the value of g, then by the numeric columns.

In [59]: bp = df_box.groupby('g').boxplot()

groupby_boxplot_vis

# Area plot

You can create area plots with Series.plot.area() (opens new window) and DataFrame.plot.area() (opens new window). Area plots are stacked by default. To produce stacked area plot, each column must be either all positive or all negative values.

When input data contains NaN, it will be automatically filled by 0. If you want to drop or fill by different values, use dataframe.dropna() or dataframe.fillna() before calling plot.

In [60]: df = pd.DataFrame(np.random.rand(10, 4), columns=['a', 'b', 'c', 'd'])

In [61]: df.plot.area();

area_plot_stacked

To produce an unstacked plot, pass stacked=False. Alpha value is set to 0.5 unless otherwise specified:

In [62]: df.plot.area(stacked=False);

area_plot_unstacked

# Scatter plot

Scatter plot can be drawn by using the DataFrame.plot.scatter() (opens new window) method. Scatter plot requires numeric columns for the x and y axes. These can be specified by the x and y keywords.

In [63]: df = pd.DataFrame(np.random.rand(50, 4), columns=['a', 'b', 'c', 'd'])

In [64]: df.plot.scatter(x='a', y='b');

scatter_plot

To plot multiple column groups in a single axes, repeat plot method specifying target ax. It is recommended to specify color and label keywords to distinguish each groups.

In [65]: ax = df.plot.scatter(x='a', y='b', color='DarkBlue', label='Group 1');

In [66]: df.plot.scatter(x='c', y='d', color='DarkGreen', label='Group 2', ax=ax);

scatter_plot_repeated

The keyword c may be given as the name of a column to provide colors for each point:

In [67]: df.plot.scatter(x='a', y='b', c='c', s=50);

scatter_plot_colored

You can pass other keywords supported by matplotlib scatter (opens new window). The example below shows a bubble chart using a column of the DataFrame as the bubble size.

In [68]: df.plot.scatter(x='a', y='b', s=df['c'] * 200);

scatter_plot_bubble

See the scatter (opens new window) method and the matplotlib scatter documentation (opens new window) for more.

# Hexagonal bin plot

You can create hexagonal bin plots with DataFrame.plot.hexbin() (opens new window). Hexbin plots can be a useful alternative to scatter plots if your data are too dense to plot each point individually.

In [69]: df = pd.DataFrame(np.random.randn(1000, 2), columns=['a', 'b'])

In [70]: df['b'] = df['b'] + np.arange(1000)

In [71]: df.plot.hexbin(x='a', y='b', gridsize=25)
Out[71]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d96e4fd0>

hexbin_plot

A useful keyword argument is gridsize; it controls the number of hexagons in the x-direction, and defaults to 100. A larger gridsize means more, smaller bins.

By default, a histogram of the counts around each (x, y) point is computed. You can specify alternative aggregations by passing values to the C and reduce_C_function arguments. C specifies the value at each (x, y) point and reduce_C_function is a function of one argument that reduces all the values in a bin to a single number (e.g. mean, max, sum, std). In this example the positions are given by columns a and b, while the value is given by column z. The bins are aggregated with NumPy’s max function.

In [72]: df = pd.DataFrame(np.random.randn(1000, 2), columns=['a', 'b'])

In [73]: df['b'] = df['b'] = df['b'] + np.arange(1000)

In [74]: df['z'] = np.random.uniform(0, 3, 1000)

In [75]: df.plot.hexbin(x='a', y='b', C='z', reduce_C_function=np.max, gridsize=25)
Out[75]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d98ea390>

hexbin_plot_agg

See the hexbin (opens new window) method and the matplotlib hexbin documentation (opens new window) for more.

# Pie plot

You can create a pie plot with DataFrame.plot.pie() (opens new window) or Series.plot.pie() (opens new window). If your data includes any NaN, they will be automatically filled with 0. A ValueError will be raised if there are any negative values in your data.

In [76]: series = pd.Series(3 * np.random.rand(4),
   ....:                    index=['a', 'b', 'c', 'd'], name='series')
   ....: 

In [77]: series.plot.pie(figsize=(6, 6))
Out[77]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da5ff278>

series_pie_plot

For pie plots it’s best to use square figures, i.e. a figure aspect ratio 1. You can create the figure with equal width and height, or force the aspect ratio to be equal after plotting by calling ax.set_aspect('equal') on the returned axes object.

Note that pie plot with DataFrame (opens new window) requires that you either specify a target column by the y argument or subplots=True. When y is specified, pie plot of selected column will be drawn. If subplots=True is specified, pie plots for each column are drawn as subplots. A legend will be drawn in each pie plots by default; specify legend=False to hide it.

In [78]: df = pd.DataFrame(3 * np.random.rand(4, 2),
   ....:                   index=['a', 'b', 'c', 'd'], columns=['x', 'y'])
   ....: 

In [79]: df.plot.pie(subplots=True, figsize=(8, 4))
Out[79]: 
array([<matplotlib.axes._subplots.AxesSubplot object at 0x7f65d915b0b8>,
       <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9493a90>],
      dtype=object)

df_pie_plot

You can use the labels and colors keywords to specify the labels and colors of each wedge.

Warning

Most pandas plots use the label and color arguments (note the lack of “s” on those). To be consistent with matplotlib.pyplot.pie() (opens new window) you must use labels and colors.

If you want to hide wedge labels, specify labels=None. If fontsize is specified, the value will be applied to wedge labels. Also, other keywords supported by matplotlib.pyplot.pie() (opens new window) can be used.

In [80]: series.plot.pie(labels=['AA', 'BB', 'CC', 'DD'], colors=['r', 'g', 'b', 'c'],
   ....:                 autopct='%.2f', fontsize=20, figsize=(6, 6))
   ....: 
Out[80]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da0be4a8>

series_pie_plot_options

If you pass values whose sum total is less than 1.0, matplotlib draws a semicircle.

In [81]: series = pd.Series([0.1] * 4, index=['a', 'b', 'c', 'd'], name='series2')

In [82]: series.plot.pie(figsize=(6, 6))
Out[82]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d92543c8>

series_pie_plot_semi

See the matplotlib pie documentation (opens new window) for more.

# Plotting with missing data

Pandas tries to be pragmatic about plotting DataFrames or Series that contain missing data. Missing values are dropped, left out, or filled depending on the plot type.

Plot Type NaN Handling
Line Leave gaps at NaNs
Line (stacked) Fill 0’s
Bar Fill 0’s
Scatter Drop NaNs
Histogram Drop NaNs (column-wise)
Box Drop NaNs (column-wise)
Area Fill 0’s
KDE Drop NaNs (column-wise)
Hexbin Drop NaNs
Pie Fill 0’s

If any of these defaults are not what you want, or if you want to be explicit about how missing values are handled, consider using fillna() (opens new window) or dropna() (opens new window) before plotting.

# Plotting Tools

These functions can be imported from pandas.plotting and take a Series (opens new window) or DataFrame (opens new window) as an argument.

# Scatter matrix plot

You can create a scatter plot matrix using the scatter_matrix method in pandas.plotting:

In [83]: from pandas.plotting import scatter_matrix

In [84]: df = pd.DataFrame(np.random.randn(1000, 4), columns=['a', 'b', 'c', 'd'])

In [85]: scatter_matrix(df, alpha=0.2, figsize=(6, 6), diagonal='kde')
Out[85]: 
array([[<matplotlib.axes._subplots.AxesSubplot object at 0x7f65dc209da0>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9df9588>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d8fb4b38>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9834128>],
       [<matplotlib.axes._subplots.AxesSubplot object at 0x7f65db04d6d8>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d8cdcc88>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d94e8278>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9a67860>],
       [<matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9a67898>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65da9f43c8>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65dacb7978>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65daddaf28>],
       [<matplotlib.axes._subplots.AxesSubplot object at 0x7f65dbe47518>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9016ac8>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d99540b8>,
        <matplotlib.axes._subplots.AxesSubplot object at 0x7f65d9f84668>]],
      dtype=object)

scatter_matrix_kde

# Density plot

You can create density plots using the Series.plot.kde() (opens new window) and DataFrame.plot.kde() (opens new window) methods.

In [86]: ser = pd.Series(np.random.randn(1000))

In [87]: ser.plot.kde()
Out[87]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d909c828>

kde_plot

# Andrews curves

Andrews curves allow one to plot multivariate data as a large number of curves that are created using the attributes of samples as coefficients for Fourier series, see the Wikipedia entry (opens new window) for more information. By coloring these curves differently for each class it is possible to visualize data clustering. Curves belonging to samples of the same class will usually be closer together and form larger structures.

Note: The “Iris” dataset is available here (opens new window).

In [88]: from pandas.plotting import andrews_curves

In [89]: data = pd.read_csv('data/iris.data')

In [90]: plt.figure()
Out[90]: <Figure size 640x480 with 0 Axes>

In [91]: andrews_curves(data, 'Name')
Out[91]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da6e5518>

andrews_curves

# Parallel coordinates

Parallel coordinates is a plotting technique for plotting multivariate data, see the Wikipedia entry (opens new window) for an introduction. Parallel coordinates allows one to see clusters in data and to estimate other statistics visually. Using parallel coordinates points are represented as connected line segments. Each vertical line represents one attribute. One set of connected line segments represents one data point. Points that tend to cluster will appear closer together.

In [92]: from pandas.plotting import parallel_coordinates

In [93]: data = pd.read_csv('data/iris.data')

In [94]: plt.figure()
Out[94]: <Figure size 640x480 with 0 Axes>

In [95]: parallel_coordinates(data, 'Name')
Out[95]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d96fbc88>

parallel_coordinates

# Lag plot

Lag plots are used to check if a data set or time series is random. Random data should not exhibit any structure in the lag plot. Non-random structure implies that the underlying data are not random. The lag argument may be passed, and when lag=1 the plot is essentially data[:-1] vs. data[1:].

In [96]: from pandas.plotting import lag_plot

In [97]: plt.figure()
Out[97]: <Figure size 640x480 with 0 Axes>

In [98]: spacing = np.linspace(-99 * np.pi, 99 * np.pi, num=1000)

In [99]: data = pd.Series(0.1 * np.random.rand(1000) + 0.9 * np.sin(spacing))

In [100]: lag_plot(data)
Out[100]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65da8b5e10>

lag_plot

# Autocorrelation plot

Autocorrelation plots are often used for checking randomness in time series. This is done by computing autocorrelations for data values at varying time lags. If time series is random, such autocorrelations should be near zero for any and all time-lag separations. If time series is non-random then one or more of the autocorrelations will be significantly non-zero. The horizontal lines displayed in the plot correspond to 95% and 99% confidence bands. The dashed line is 99% confidence band. See the Wikipedia entry (opens new window) for more about autocorrelation plots.

In [101]: from pandas.plotting import autocorrelation_plot

In [102]: plt.figure()
Out[102]: <Figure size 640x480 with 0 Axes>

In [103]: spacing = np.linspace(-9 * np.pi, 9 * np.pi, num=1000)

In [104]: data = pd.Series(0.7 * np.random.rand(1000) + 0.3 * np.sin(spacing))

In [105]: autocorrelation_plot(data)
Out[105]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d19556d8>

autocorrelation_plot

# Bootstrap plot

Bootstrap plots are used to visually assess the uncertainty of a statistic, such as mean, median, midrange, etc. A random subset of a specified size is selected from a data set, the statistic in question is computed for this subset and the process is repeated a specified number of times. Resulting plots and histograms are what constitutes the bootstrap plot.

In [106]: from pandas.plotting import bootstrap_plot

In [107]: data = pd.Series(np.random.rand(1000))

In [108]: bootstrap_plot(data, size=50, samples=500, color='grey')
Out[108]: <Figure size 640x480 with 6 Axes>

bootstrap_plot

# RadViz

RadViz is a way of visualizing multi-variate data. It is based on a simple spring tension minimization algorithm. Basically you set up a bunch of points in a plane. In our case they are equally spaced on a unit circle. Each point represents a single attribute. You then pretend that each sample in the data set is attached to each of these points by a spring, the stiffness of which is proportional to the numerical value of that attribute (they are normalized to unit interval). The point in the plane, where our sample settles to (where the forces acting on our sample are at an equilibrium) is where a dot representing our sample will be drawn. Depending on which class that sample belongs it will be colored differently. See the R package Radviz (opens new window) for more information.

Note: The “Iris” dataset is available here (opens new window).

In [109]: from pandas.plotting import radviz

In [110]: data = pd.read_csv('data/iris.data')

In [111]: plt.figure()
Out[111]: <Figure size 640x480 with 0 Axes>

In [112]: radviz(data, 'Name')
Out[112]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65f66bd630>

radviz

# Plot Formatting

# Setting the plot style

From version 1.5 and up, matplotlib offers a range of pre-configured plotting styles. Setting the style can be used to easily give plots the general look that you want. Setting the style is as easy as calling matplotlib.style.use(my_plot_style) before creating your plot. For example you could write matplotlib.style.use('ggplot') for ggplot-style plots.

You can see the various available style names at matplotlib.style.available and it’s very easy to try them out.

# General plot style arguments

Most plotting methods have a set of keyword arguments that control the layout and formatting of the returned plot:

In [113]: plt.figure();

In [114]: ts.plot(style='k--', label='Series');

series_plot_basic2

For each kind of plot (e.g. line, bar, scatter) any additional arguments keywords are passed along to the corresponding matplotlib function (ax.plot() (opens new window), ax.bar() (opens new window), ax.scatter() (opens new window)). These can be used to control additional styling, beyond what pandas provides.

# Controlling the legend

You may set the legend argument to False to hide the legend, which is shown by default.

In [115]: df = pd.DataFrame(np.random.randn(1000, 4),
   .....:                   index=ts.index, columns=list('ABCD'))
   .....: 

In [116]: df = df.cumsum()

In [117]: df.plot(legend=False)
Out[117]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65dbdbc0f0>

frame_plot_basic_noleg

# Scales

You may pass logy to get a log-scale Y axis.

In [118]: ts = pd.Series(np.random.randn(1000),
   .....:                index=pd.date_range('1/1/2000', periods=1000))
   .....: 

In [119]: ts = np.exp(ts.cumsum())

In [120]: ts.plot(logy=True)
Out[120]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65dbefdf98>

series_plot_logy

See also the logx and loglog keyword arguments.

# Plotting on a secondary y-axis

To plot data on a secondary y-axis, use the secondary_y keyword:

In [121]: df.A.plot()
Out[121]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65f8ef6b00>

In [122]: df.B.plot(secondary_y=True, style='g')
Out[122]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65f6297780>

series_plot_secondary_y

To plot some columns in a DataFrame, give the column names to the secondary_y keyword:

In [123]: plt.figure()
Out[123]: <Figure size 640x480 with 0 Axes>

In [124]: ax = df.plot(secondary_y=['A', 'B'])

In [125]: ax.set_ylabel('CD scale')
Out[125]: Text(0, 0.5, 'CD scale')

In [126]: ax.right_ax.set_ylabel('AB scale')
Out[126]: Text(0, 0.5, 'AB scale')

frame_plot_secondary_y

Note that the columns plotted on the secondary y-axis is automatically marked with “(right)” in the legend. To turn off the automatic marking, use the mark_right=False keyword:

In [127]: plt.figure()
Out[127]: <Figure size 640x480 with 0 Axes>

In [128]: df.plot(secondary_y=['A', 'B'], mark_right=False)
Out[128]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65f6102390>

frame_plot_secondary_y_no_right

# Suppressing tick resolution adjustment

pandas includes automatic tick resolution adjustment for regular frequency time-series data. For limited cases where pandas cannot infer the frequency information (e.g., in an externally created twinx), you can choose to suppress this behavior for alignment purposes.

Here is the default behavior, notice how the x-axis tick labeling is performed:

In [129]: plt.figure()
Out[129]: <Figure size 640x480 with 0 Axes>

In [130]: df.A.plot()
Out[130]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65dc39f978>

ser_plot_suppress

Using the x_compat parameter, you can suppress this behavior:

In [131]: plt.figure()
Out[131]: <Figure size 640x480 with 0 Axes>

In [132]: df.A.plot(x_compat=True)
Out[132]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65dc39f1d0>

ser_plot_suppress_parm

If you have more than one plot that needs to be suppressed, the use method in pandas.plotting.plot_params can be used in a with statement:

In [133]: plt.figure()
Out[133]: <Figure size 640x480 with 0 Axes>

In [134]: with pd.plotting.plot_params.use('x_compat', True):
   .....:     df.A.plot(color='r')
   .....:     df.B.plot(color='g')
   .....:     df.C.plot(color='b')
   .....:

ser_plot_suppress_context

# Automatic date tick adjustment

New in version 0.20.0.

TimedeltaIndex now uses the native matplotlib tick locator methods, it is useful to call the automatic date tick adjustment from matplotlib for figures whose ticklabels overlap.

See the autofmt_xdate method and the matplotlib documentation (opens new window) for more.

# Subplots

Each Series in a DataFrame can be plotted on a different axis with the subplots keyword:

In [135]: df.plot(subplots=True, figsize=(6, 6));

frame_plot_subplots

# Using layout and targeting multiple axes

The layout of subplots can be specified by the layout keyword. It can accept (rows, columns). The layout keyword can be used in hist and boxplot also. If the input is invalid, a ValueError will be raised.

The number of axes which can be contained by rows x columns specified by layout must be larger than the number of required subplots. If layout can contain more axes than required, blank axes are not drawn. Similar to a NumPy array’s reshape method, you can use -1 for one dimension to automatically calculate the number of rows or columns needed, given the other.

In [136]: df.plot(subplots=True, layout=(2, 3), figsize=(6, 6), sharex=False);

frame_plot_subplots_layout

The above example is identical to using:

In [137]: df.plot(subplots=True, layout=(2, -1), figsize=(6, 6), sharex=False);

The required number of columns (3) is inferred from the number of series to plot and the given number of rows (2).

You can pass multiple axes created beforehand as list-like via ax keyword. This allows more complicated layouts. The passed axes must be the same number as the subplots being drawn.

When multiple axes are passed via the ax keyword, layout, sharex and sharey keywords don’t affect to the output. You should explicitly pass sharex=False and sharey=False, otherwise you will see a warning.

In [138]: fig, axes = plt.subplots(4, 4, figsize=(6, 6))

In [139]: plt.subplots_adjust(wspace=0.5, hspace=0.5)

In [140]: target1 = [axes[0][0], axes[1][1], axes[2][2], axes[3][3]]

In [141]: target2 = [axes[3][0], axes[2][1], axes[1][2], axes[0][3]]

In [142]: df.plot(subplots=True, ax=target1, legend=False, sharex=False, sharey=False);

In [143]: (-df).plot(subplots=True, ax=target2, legend=False,
   .....:            sharex=False, sharey=False);
   .....:

frame_plot_subplots_multi_ax

Another option is passing an ax argument to Series.plot() (opens new window) to plot on a particular axis:

In [144]: fig, axes = plt.subplots(nrows=2, ncols=2)

In [145]: df['A'].plot(ax=axes[0, 0]);

In [146]: axes[0, 0].set_title('A');

In [147]: df['B'].plot(ax=axes[0, 1]);

In [148]: axes[0, 1].set_title('B');

In [149]: df['C'].plot(ax=axes[1, 0]);

In [150]: axes[1, 0].set_title('C');

In [151]: df['D'].plot(ax=axes[1, 1]);

In [152]: axes[1, 1].set_title('D');

series_plot_multi

# Plotting with error bars

Plotting with error bars is supported in DataFrame.plot() (opens new window) and Series.plot() (opens new window).

Horizontal and vertical error bars can be supplied to the xerr and yerr keyword arguments to plot() (opens new window). The error values can be specified using a variety of formats:

Asymmetrical error bars are also supported, however raw error values must be provided in this case. For a M length Series (opens new window), a Mx2 array should be provided indicating lower and upper (or left and right) errors. For a MxN DataFrame (opens new window), asymmetrical errors should be in a Mx2xN array.

Here is an example of one way to easily plot group means with standard deviations from the raw data.

# Generate the data
In [153]: ix3 = pd.MultiIndex.from_arrays([
   .....:     ['a', 'a', 'a', 'a', 'b', 'b', 'b', 'b'],
   .....:     ['foo', 'foo', 'bar', 'bar', 'foo', 'foo', 'bar', 'bar']],
   .....:     names=['letter', 'word'])
   .....: 

In [154]: df3 = pd.DataFrame({'data1': [3, 2, 4, 3, 2, 4, 3, 2],
   .....:                     'data2': [6, 5, 7, 5, 4, 5, 6, 5]}, index=ix3)
   .....: 

# Group by index labels and take the means and standard deviations
# for each group
In [155]: gp3 = df3.groupby(level=('letter', 'word'))

In [156]: means = gp3.mean()

In [157]: errors = gp3.std()

In [158]: means
Out[158]: 
             data1  data2
letter word              
a      bar     3.5    6.0
       foo     2.5    5.5
b      bar     2.5    5.5
       foo     3.0    4.5

In [159]: errors
Out[159]: 
                data1     data2
letter word                    
a      bar   0.707107  1.414214
       foo   0.707107  0.707107
b      bar   0.707107  0.707107
       foo   1.414214  0.707107

# Plot
In [160]: fig, ax = plt.subplots()

In [161]: means.plot.bar(yerr=errors, ax=ax, capsize=4)
Out[161]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d1048400>

errorbar_example

# Plotting tables

Plotting with matplotlib table is now supported in DataFrame.plot() (opens new window) and Series.plot() (opens new window) with a table keyword. The table keyword can accept bool, DataFrame (opens new window) or Series (opens new window). The simple way to draw a table is to specify table=True. Data will be transposed to meet matplotlib’s default layout.

In [162]: fig, ax = plt.subplots(1, 1)

In [163]: df = pd.DataFrame(np.random.rand(5, 3), columns=['a', 'b', 'c'])

In [164]: ax.get_xaxis().set_visible(False)   # Hide Ticks

In [165]: df.plot(table=True, ax=ax)
Out[165]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0ff7550>

line_plot_table_true

Also, you can pass a different DataFrame (opens new window) or Series (opens new window) to the table keyword. The data will be drawn as displayed in print method (not transposed automatically). If required, it should be transposed manually as seen in the example below.

In [166]: fig, ax = plt.subplots(1, 1)

In [167]: ax.get_xaxis().set_visible(False)   # Hide Ticks

In [168]: df.plot(table=np.round(df.T, 2), ax=ax)
Out[168]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0efdcc0>

line_plot_table_data

There also exists a helper function pandas.plotting.table, which creates a table from DataFrame (opens new window) or Series (opens new window), and adds it to an matplotlib.Axes instance. This function can accept keywords which the matplotlib table (opens new window) has.

In [169]: from pandas.plotting import table

In [170]: fig, ax = plt.subplots(1, 1)

In [171]: table(ax, np.round(df.describe(), 2),
   .....:       loc='upper right', colWidths=[0.2, 0.2, 0.2])
   .....: 
Out[171]: <matplotlib.table.Table at 0x7f65d0e61b38>

In [172]: df.plot(ax=ax, ylim=(0, 2), legend=None)
Out[172]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0eab358>

line_plot_table_describe

Note: You can get table instances on the axes using axes.tables property for further decorations. See the matplotlib table documentation (opens new window) for more.

# Colormaps

A potential issue when plotting a large number of columns is that it can be difficult to distinguish some series due to repetition in the default colors. To remedy this, DataFrame plotting supports the use of the colormap argument, which accepts either a Matplotlib colormap (opens new window) or a string that is a name of a colormap registered with Matplotlib. A visualization of the default matplotlib colormaps is available here (opens new window).

As matplotlib does not directly support colormaps for line-based plots, the colors are selected based on an even spacing determined by the number of columns in the DataFrame. There is no consideration made for background color, so some colormaps will produce lines that are not easily visible.

To use the cubehelix colormap, we can pass colormap='cubehelix'.

In [173]: df = pd.DataFrame(np.random.randn(1000, 10), index=ts.index)

In [174]: df = df.cumsum()

In [175]: plt.figure()
Out[175]: <Figure size 640x480 with 0 Axes>

In [176]: df.plot(colormap='cubehelix')
Out[176]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0defdd8>

cubehelix

Alternatively, we can pass the colormap itself:

In [177]: from matplotlib import cm

In [178]: plt.figure()
Out[178]: <Figure size 640x480 with 0 Axes>

In [179]: df.plot(colormap=cm.cubehelix)
Out[179]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0c22a90>

cubehelix_cm

Colormaps can also be used other plot types, like bar charts:

In [180]: dd = pd.DataFrame(np.random.randn(10, 10)).applymap(abs)

In [181]: dd = dd.cumsum()

In [182]: plt.figure()
Out[182]: <Figure size 640x480 with 0 Axes>

In [183]: dd.plot.bar(colormap='Greens')
Out[183]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d0a5de10>

greens

Parallel coordinates charts:

In [184]: plt.figure()
Out[184]: <Figure size 640x480 with 0 Axes>

In [185]: parallel_coordinates(data, 'Name', colormap='gist_rainbow')
Out[185]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d08e5eb8>

parallel_gist_rainbow

Andrews curves charts:

In [186]: plt.figure()
Out[186]: <Figure size 640x480 with 0 Axes>

In [187]: andrews_curves(data, 'Name', colormap='winter')
Out[187]: <matplotlib.axes._subplots.AxesSubplot at 0x7f65d06b6518>

andrews_curve_winter

# Plotting directly with matplotlib

In some situations it may still be preferable or necessary to prepare plots directly with matplotlib, for instance when a certain type of plot or customization is not (yet) supported by pandas. Series and DataFrame objects behave like arrays and can therefore be passed directly to matplotlib functions without explicit casts.

pandas also automatically registers formatters and locators that recognize date indices, thereby extending date and time support to practically all plot types available in matplotlib. Although this formatting does not provide the same level of refinement you would get when plotting via pandas, it can be faster when plotting a large number of points.

In [188]: price = pd.Series(np.random.randn(150).cumsum(),
   .....:                   index=pd.date_range('2000-1-1', periods=150, freq='B'))
   .....: 

In [189]: ma = price.rolling(20).mean()

In [190]: mstd = price.rolling(20).std()

In [191]: plt.figure()
Out[191]: <Figure size 640x480 with 0 Axes>

In [192]: plt.plot(price.index, price, 'k')
Out[192]: [<matplotlib.lines.Line2D at 0x7f65da5f8710>]

In [193]: plt.plot(ma.index, ma, 'b')
Out[193]: [<matplotlib.lines.Line2D at 0x7f65d9ab9518>]

In [194]: plt.fill_between(mstd.index, ma - 2 * mstd, ma + 2 * mstd,
   .....:                  color='b', alpha=0.2)
   .....: 
Out[194]: <matplotlib.collections.PolyCollection at 0x7f65d9ab9128>

bollinger

# Trellis plotting interface

Warning

The rplot trellis plotting interface has been removed. Please use external packages like seaborn (opens new window) for similar but more refined functionality and refer to our 0.18.1 documentation here (opens new window) for how to convert to using it.