在条形图上格式化日期标签 [英] Formatting date labels on bar plot

问题描述

我的问题

假设我有一个这样的系列.

在[10]:month_series出[10]:2016-01-01 48802016-02-01 45792016-03-01 67262016-04-01 17782016-05-01 33032016-06-01 54022016-07-01 12072016-08-01 61762016-09-01 55862016-10-01 28022016-11-01 69442016-12-01 35802017-01-01 9336dtype:int64

我只想构建一个条形图来比较月与月，这对于

来说似乎很简单

 在[11]中:month_series.plot(kind ='bar')出[11]:

我真的不需要更多，但是我的问题是日期在x轴上看起来很糟糕-我后来想格式化日期，以便只提供年份和月份，例如%Y-%m.我该怎么做?

<小时>

我的挣扎

因此，查看

此时我非常确信我遗漏了一些东西，并且有一种非常简单的方法可以做到这一点.

解决方案

您可以使用 matplotlib.axes.Axes.set_xticklabels 其参数 labels 接受一个字符串，如序列(任何可通过 "%s" 转换打印的内容)，然后使用

My question

Suppose I have a Series like this.

In[10]: month_series
Out[10]: 
2016-01-01    4880
2016-02-01    4579
2016-03-01    6726
2016-04-01    1778
2016-05-01    3303
2016-06-01    5402
2016-07-01    1207
2016-08-01    6176
2016-09-01    5586
2016-10-01    2802
2016-11-01    6944
2016-12-01    3580
2017-01-01    9336
dtype: int64

I want to just construct a bar plot to compare month to month, which seems quite simple with

In[11]: month_series.plot(kind='bar')
Out[11]: 

I really don't need anything much more than that, but my issue is that the dates look terrible on the x-axis - I subsequently wanted to format the dates so that I just provide the year and month, some format like %Y-%m. How can I do so?

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My struggles

So, looking at the documentation for pandas.Series.plot I see the xticks argument that can be passed, and figure I can use strftime to format the dates and pass as a sequence.. but this doesn't work because the ticks require numerical values or dates, not strings.

So then I figure I should just use raw matplotlib instead, so that I can use set_major_formatter with a DateFormatter to modify the tick labels. But if I just use plt.bar, that introduces a new issue - the entire date range is used, which makes sense.

In[17]: plt.bar(month_sereis.index, month_sereis.values)
Out[17]: <Container object of 13 artists>  

At this point I'm quite convinced I'm missing something and there's a trivially simple way to do this.

解决方案

You can make use of matplotlib.axes.Axes.set_xticklabels whose argument labels accepts a string like sequence (anything printable with "%s" conversion) and then make use of DateTimeIndex.strftime to specify the format you'd want the labels to appear in.

ax = month_series.plot.bar()
# ax.set_xticklabels(month_series.index.to_period('M')) also works 
ax.set_xticklabels(month_series.index.strftime('%Y-%m'))
plt.show()

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