保存由函数 matplotlib python 产生的绘图

2022-01-24 00:00:00 python matplotlib jpeg ipython save

问题描述

我创建了一个函数，它从数据集中获取一系列值并输出一个图.例如:

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) 将返回函数中指定温度范围内的降水图.

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

假设我想保存加利福尼亚温度在 60-70F 之间的图.因此，我将调用我的函数 my_plot(California, 60, 70) 并在温度介于 60 和 70F 之间时获得加利福尼亚的降水图.

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.

我的问题是:如何将调用函数产生的绘图保存为 jpeg 格式?

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

我知道 plt.savefig() 不是调用函数的结果，但在我的情况下，我该怎么做?

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

谢谢！

更多细节:这是我的代码(高度简化):

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()

然后我将这个函数称为如下:my_plot(California, 60, 70) 我得到了 60-70 温度范围的图.如何在函数定义中不包含 savefig 的情况下保存此图(这是因为我需要更改最低和最高温度参数.

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.

解决方案

将 figure 的引用指向某个变量，并从函数中返回:

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

调用该函数时，可以使用引用保存图形:

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

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

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