save a plot resulting from a function matplotlib python

问题

I created a function that takes a range of values from a data set and outputs a plot. For instance:

my_plot(location_dataset, min_temperature, max_temperature) will return a plot of precipitation for the range of temperature specified in the function.

Let's say I want to save the plot for the temperature between 60-70F in California. so, I would call my function my_plot(California, 60, 70) and will get a plot of precipitation for California when temperatures are between 60 and 70F.

My question is: how do I save a plot that results from calling a function into a jpeg format?

I know of plt.savefig() when it is not the result of calling a function but in my case how do I do this?

Thanks!

More details: here is my code (heavily simplified):

import matplotlib.pyplot as plt

def my_plot(location_dataset, min_temperature, max_temperature):
    condition = (location_dataset['temperature'] > min_temperature) & (dataset['temperature'] <= max_temperature)
    subset = location_dataset[condition] # subset the data based on the temperature range

    x = subset['precipitation'] # takes the precipitation column only
    plt.figure(figsize=(8, 6))
    plt.plot(x)
    plt.show()

So then I call this function as follow: my_plot(California, 60, 70) and I get my plot for the 60-70 temperature range. how do I save this plot without having the savefig inside the function definition (and that is because I need to change the min and max temperature parameters.

回答1:

Take the reference to the figure to some variable, and return it from your function:

import matplotlib.pyplot as plt

def my_plot(location_dataset, min_temperature, max_temperature):
    condition = (location_dataset['temperature'] > min_temperature) & (dataset['temperature'] <= max_temperature)
    subset = location_dataset[condition] # subset the data based on the temperature range

    x = subset['precipitation'] # takes the precipitation column only
    # N.B. referenca taken to fig
    fig = plt.figure(figsize=(8, 6))
    plt.plot(x)
    plt.show()

    return fig

When you call this function, you can use the reference for saving the figure:

fig = my_plot(...)
fig.savefig("somefile.png")

来源：https://stackoverflow.com/questions/24791709/save-a-plot-resulting-from-a-function-matplotlib-python