时间戳

首页 > 解决方案 > adding dates to x-axis of stacked area chart

python - adding dates to x-axis of stacked area chart

问题描述

I'm fairly new to Python and I'm trying to add dates to the bottom of a stacked area chart, but I'm running into some errors that I can't resolve. Example of the chart I'm working with: tried

So far, I've found https://matplotlib.org/3.1.1/gallery/text_labels_and_annotations/date.html helpful, but I'm unable to implement some portions of the code because I'm running into some errors that I can't quite resolve.

area_plot = (df.pivot(index='login_month',
          columns='user_month_created',
          values='cumulative_logins')
   .plot.area(figsize=(20,18))
)

#labels
plt.title('cumulative monthly logins by user creation cohort month')
plt.xlabel('login month')
plt.ylabel('cumulative monthly logins (in tens of millions)')

#ticks

# plt.xticks(x, 'bbbb')
years = mdates.YearLocator()   # every year
months = mdates.MonthLocator()  # every month
years_fmt = mdates.DateFormatter('%Y')

# format the ticks
area_plot.xaxis.set_major_locator(years)
area_plot.xaxis.set_major_formatter(years_fmt)
area_plot.xaxis.set_minor_locator(months)

# round to nearest years.
datemin = np.datetime64(df['login_month'][0], 'Y')
datemax = np.datetime64(df['login_month'][-1], 'Y') + np.timedelta64(1, 'Y')
area_plot.set_xlim(datemin, datemax)

plt.xticks()
plt.yticks(np.arange(0, 11000000, 250000))

plt.grid(True)
plt.plot()

I expected the years to show up on the x-axis (and I was going to edit it to appear in a "Mon YYYY" format), but I get the error below:

KeyError -1 ---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-102-5fb53d3f1bb7> in <module>
     24 # round to nearest years.
     25 datemin = np.datetime64(df['login_month'][0], 'Y')
---> 26 datemax = np.datetime64(df['login_month'][-1], 'Y') + np.timedelta64(1, 'Y')
     27 area_plot.set_xlim(datemin, datemax)
     28 

/opt/conda/envs/python3/lib/python3.6/site-packages/pandas/core/series.py in __getitem__(self, key)
    765         key = com._apply_if_callable(key, self)
    766         try:
--> 767             result = self.index.get_value(self, key)
    768 
    769             if not is_scalar(result):

/opt/conda/envs/python3/lib/python3.6/site-packages/pandas/core/indexes/base.py in get_value(self, series, key)
   3116         try:
   3117             return self._engine.get_value(s, k,
-> 3118                                           tz=getattr(series.dtype, 'tz', None))
   3119         except KeyError as e1:
   3120             if len(self) > 0 and self.inferred_type in ['integer', 'boolean']:

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_value()

pandas/_libs/index.pyx in pandas._libs.index.IndexEngine.get_loc()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item()

pandas/_libs/hashtable_class_helper.pxi in pandas._libs.hashtable.Int64HashTable.get_item()

KeyError: -1

I don't really know what I'm doing wrong here.

Edit 1:

My login_month data looks like the following

   signup_month  login_month  cumulative_logins
0  2016-01       2016-02      16
1  2016-01       2016-03      20
2  2016-01       2016-04      26
3  2016-01       2016-05      29
4  2016-02       2016-03      10
5  2016-02       2016-04      15
6  2016-02       2016-05      20
7  2016-03       2016-04      13
8  2016-03       2016-05      23
9  2016-04       2016-05      35

标签： pythonnumpymatplotlibchartsdata-visualization

解决方案

例外：

KeyError: -1

表示-1不是 的有效键df['login_month']。我不熟悉df为您创建的模块，但我建议您查看其文档或转储所有df['login_month']'s 键，以便您了解可能的有效用法。

推荐阅读