matplotlib.rst

Matplotlib

Using pictures.add() <xlwings.main.Pictures.add>, it is easy to paste a Matplotlib plot as picture in Excel.

Getting started

The easiest sample boils down to:

>>> import matplotlib.pyplot as plt
>>> import xlwings as xw

>>> fig = plt.figure()
>>> plt.plot([1, 2, 3])

>>> sht = xw.Book().sheets[0]
>>> sht.pictures.add(fig, name='MyPlot', update=True)

Note

If you set update=True, you can resize and position the plot on Excel: subsequent calls to pictures.add() with the same name ('MyPlot') will update the picture without changing its position or size.

Full integration with Excel

Calling the above code with RunPython <run_python> and binding it e.g. to a button is straightforward and works cross-platform.

However, on Windows you can make things feel even more integrated by setting up a UDF <udfs> along the following lines:

@xw.func
def myplot(n):
    sht = xw.Book.caller().sheets.active
    fig = plt.figure()
    plt.plot(range(int(n)))
    sht.pictures.add(fig, name='MyPlot', update=True)
    return 'Plotted with n={}'.format(n)

If you import this function and call it from cell B2, then the plot gets automatically updated when cell B1 changes:

Properties

Size, position and other properties can either be set as arguments within pictures.add() <xlwings.main.Pictures.add>, or by manipulating the picture object that is returned, see xlwings.Picture.

For example:

>>> sht = xw.Book().sheets[0]
>>> sht.pictures.add(fig, name='MyPlot', update=True,
                     left=sht.range('B5').left, top=sht.range('B5').top)

or:

>>> plot = sht.pictures.add(fig, name='MyPlot', update=True)
>>> plot.height /= 2
>>> plot.width /= 2

Getting a Matplotlib figure

Here are a few examples of how you get a matplotlib figure object:

• via PyPlot interface:

  import matplotlib.pyplot as plt
  fig = plt.figure()
  plt.plot([1, 2, 3, 4, 5])

  or:

  import matplotlib.pyplot as plt
  plt.plot([1, 2, 3, 4, 5])
  fig = plt.gcf()

• via object oriented interface:

  from matplotlib.figure import Figure
  fig = Figure(figsize=(8, 6))
  ax = fig.add_subplot(111)
  ax.plot([1, 2, 3, 4, 5])

• via Pandas:

  import pandas as pd
  import numpy as np
  
  df = pd.DataFrame(np.random.rand(10, 4), columns=['a', 'b', 'c', 'd'])
  ax = df.plot(kind='bar')
  fig = ax.get_figure()