为什么plt.hline（）比数据中的日期数量显示长X轴的延长X轴？ - matplotlib

发布于 2025-02-13 03:47:26 字数 924 浏览 3 评论 0原文

我试图复制一个绘图示例，但遇到了X轴和日期范围的问题。当包括plt.hlines（）时，范围可以追溯到1970年。删除时，日期范围是正确的。什么可能导致这个问题？

import yfinance as yf
import matplotlib.pyplot as plt

AAPL = yf.download('AAPL', start = '2020-4-5', end = '2021-6-5',)

data = AAPL['Close']
mean = AAPL['Close'].mean()
std = AAPL['Close'].std()
min_value = min(data)
max_value = max(data)

plt.title("AAPL")
plt.ylim(min_value -20, max_value + 20)
plt.scatter(x=AAPL.index, y=AAPL['Close'])
plt.hlines(y=mean, xmin=0, xmax=len(data))  # If this line is Removed, the X axis works with Date Range.
plt.show()

原文

I'm trying to replicate a plot example but ran into an issue with the x axis and date range. When the plt.hlines() is included, the range goes back to 1970. When removed, the date range is correct. What could be causing the issue?

import yfinance as yf
import matplotlib.pyplot as plt

AAPL = yf.download('AAPL', start = '2020-4-5', end = '2021-6-5',)

data = AAPL['Close']
mean = AAPL['Close'].mean()
std = AAPL['Close'].std()
min_value = min(data)
max_value = max(data)

plt.title("AAPL")
plt.ylim(min_value -20, max_value + 20)
plt.scatter(x=AAPL.index, y=AAPL['Close'])
plt.hlines(y=mean, xmin=0, xmax=len(data))  # If this line is Removed, the X axis works with Date Range.
plt.show()

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旧时光的容颜 2025-02-20 03:47:26

问题是：

plt.hlines(y=mean, xmin=0, xmax=len(data))  # If this line is Removed, the X axis works with Date Range.

您的数据点具有start ='2020-4-5'，end ='2021-6-5'之间的数据

，但是当您使用hlines时（水平线），XMIN和Xmax函数是参数，而不是您假设它们的参数。

https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.hlines.html

xmin，xmax和每行的结尾。如果提供标量，所有线路将具有相同的长度。

设置xmax = len（data）时，您要求len（data）“单位”要显示在X轴上。

当您在代码段中删除该plt.hlines时，您实际上是要求matplotlib自动确定X轴范围，这就是为什么它可以使用。

也许您要寻找的是指定日期范围，例如

plt.xlim([datetime.date(2020, 4, 5), datetime.date(2021, 6, 5)])

完整示例：

import datetime
import yfinance as yf
import matplotlib.pyplot as plt

AAPL = yf.download('AAPL', start = '2020-4-5', end = '2021-6-5',)

data = AAPL['Close']
mean = AAPL['Close'].mean()
std = AAPL['Close'].std()
min_value = min(data)
max_value = max(data)

plt.title("AAPL")
plt.ylim(min_value -20, max_value + 20)
plt.xlim([datetime.date(2020, 4, 5), datetime.date(2021, 6, 5)])
plt.scatter(x=AAPL.index, y=AAPL['Close'])
plt.show()

The issue is with:

plt.hlines(y=mean, xmin=0, xmax=len(data))  # If this line is Removed, the X axis works with Date Range.

Your data points has data between start = '2020-4-5', end = '2021-6-5'

But when you use the hlines (horizontal line), the xmin and xmax functions are the arguments not what you were assuming them to be.

https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.hlines.html

xmin, xmax refers to the respective beginning and end of each line. If scalars are provided, all lines will have same length.

When you set the xmax=len(data), you are asking for len(data) "units" to be shown on the x-axis.

When you remove that plt.hlines in your code snippet, you are essentially asking matplotlib to automatically determine the x-axis range, that is why it worked.

Perhaps what you are looking for is to specify the date-range, e.g.

plt.xlim([datetime.date(2020, 4, 5), datetime.date(2021, 6, 5)])

Full example:

import datetime
import yfinance as yf
import matplotlib.pyplot as plt

AAPL = yf.download('AAPL', start = '2020-4-5', end = '2021-6-5',)

data = AAPL['Close']
mean = AAPL['Close'].mean()
std = AAPL['Close'].std()
min_value = min(data)
max_value = max(data)

plt.title("AAPL")
plt.ylim(min_value -20, max_value + 20)
plt.xlim([datetime.date(2020, 4, 5), datetime.date(2021, 6, 5)])
plt.scatter(x=AAPL.index, y=AAPL['Close'])
plt.show()