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Description
Problem
I would like to have the options to determine how the legend should be filled, i.e. rowwise or columnwise. At the moment the rows are filled first. For example:
x = np.arange(0, 10)
fig, ax = plt.subplots()
ax.plot(x, x, label='1')
ax.plot(x, x+1, label='2')
ax.plot(x, x+ 2, label='3')
ax.plot(x, x+3, label='4')
ax.legend(ncols=2)
plt.show()
The legend looks like:
| 1 | 3 |
|---|---|
| 2 | 4 |
What I would like is:
| 1 | 2 |
|---|---|
| 3 | 4 |
Proposed solution
Not my own solution, but found here: https://stackoverflow.com/questions/10101141/matplotlib-legend-add-items-across-columns-instead-of-down
One way to implement this is to add a keyword and use this function:
def flip(items, ncol):
"""
Flips the order of items in a list by grouping them into columns.
*used to fill columns of legends first*
Parameters:
items (list): The list of items to be flipped.
ncol (int): The number of columns to group the items into.
Returns:
itertools.chain: A chain object containing the flipped items.
Source:
https://stackoverflow.com/questions/10101141/
matplotlib-legend-add-items-across-columns-instead-of-down
"""
return itertools.chain(*[items[i::ncol] for i in range(ncol)])
handles, labels = axs.get_legend_handles_labels()
ncol = 2
ax.legend(flip(handles, ncol), flip(labels, ncol), ncol=ncol)At the moment it is a seperate function, but based on an extra keyword-argument one could check if the labels should be distributed column or row wise and use the ncol argument to change this.