在 matplotlib 中格式化日期时间 xlabels（pandas df.plot() 方法）
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Formatting datetime xlabels in matplotlib (pandas df.plot() method)
提问by Dan
I can't figure out how to change the format of these x-labels. Ideally, I'd like to call strftime('%Y-%m-%d')on them. I've tried things like set_major_formatterbut was unsuccessful.
我不知道如何更改这些 x 标签的格式。理想情况下，我想拜访strftime('%Y-%m-%d')他们。我尝试过类似的事情，set_major_formatter但没有成功。
import pandas as pd
import numpy as np
date_range = pd.date_range('2014-01-01', '2015-01-01', freq='MS')
df = pd.DataFrame({'foo': np.random.randint(0, 10, len(date_range))}, index=date_range)
ax = df.plot(kind='bar')
采纳答案by wflynny
The objects in the date_rangeDF are Timestampobjects. Call Timestamp.strftimeon each object:
在对象date_rangeDF的Timestamp对象。调用Timestamp.strftime每个对象：
date_range = pd.date_range('2014-01-01', '2015-01-01', freq='MS')
date_range = date_range.map(lambda t: t.strftime('%Y-%m-%d'))
print date_range
array([2014-01-01, 2014-02-01, 2014-03-01, 2014-04-01, 2014-05-01,
2014-06-01, 2014-07-01, 2014-08-01, 2014-09-01, 2014-10-01,
2014-11-01, 2014-12-01, 2015-01-01], dtype=object)
This allows for more general formatting options versus truncating the ticklabel string.
与截断刻度标签字符串相比，这允许使用更通用的格式选项。
回答by CT Zhu
Simply access the tick labels and change them:
只需访问刻度标签并更改它们：
xtl=[item.get_text()[:10] for item in ax.get_xticklabels()]
_=ax.set_xticklabels(xtl)
回答by RCCG
You could just pass new labels exactly with your preferred strftime:
您可以完全使用您喜欢的 strftime 传递新标签：
ax.set_xticklabels([pandas_datetime.strftime("%Y-%m-%d") for pandas_datetime in df.index])
It's not the prettiest answer, but it gets the job done consistently.
这不是最漂亮的答案，但它始终如一地完成工作。
