我有一个时间序列数据框,我从datetime列计算了一个季节列。然后我按“季节”和“年份”将数据框索引,并想要绘制结果。代码如下:
In [1]: measurement = np.array([1,2,3,4,5,5,6,7,8,5,4,5])
...: lower_bound = 3.5
...: higher_bound = 5.5
...: N = 3
...:
In [2]: m2D = measurement[np.arange(N) + np.arange(len(measurement)-N+1)[:,None]]
In [3]: m2D # Notice that is a 2D array (shifted) version of input
Out[3]:
array([[1, 2, 3],
[2, 3, 4],
[3, 4, 5],
[4, 5, 5],
[5, 5, 6],
[5, 6, 7],
[6, 7, 8],
[7, 8, 5],
[8, 5, 4],
[5, 4, 5]])
In [4]: np.nonzero(np.all((lower_bound < m2D) & (higher_bound > m2D),axis=1))[0][0]
Out[4]: 3
不幸的是,这在绘制x轴标签时给出了错误:
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as mdates
dates = pd.date_range('20070101',periods=1000)
df = pd.DataFrame(np.random.randn(1000), columns =list ('A'))
df['date'] = dates
def get_season(row):
if row['date'].month >= 3 and row['date'].month <= 5:
return 'spring'
elif row['date'].month >= 6 and row['date'].month <= 8:
return 'summer'
elif row['date'].month >= 9 and row['date'].month <= 11:
return 'autumn'
else:
return 'winter'
df['Season'] = df.apply(get_season, axis=1)
df['Year'] = df['date'].dt.year
df.loc[df['date'].dt.month == 12, 'Year'] += 1
df = df.set_index(['Year', 'Season'], inplace=False)
df.head()
fig,ax = plt.subplots()
df.plot(x_compat=True,ax=ax)
ax.xaxis.set_tick_params(reset=True)
ax.xaxis.set_major_locator(mdates.YearLocator(1))
ax.xaxis.set_major_formatter(mdates.DateFormatter('%Y'))
plt.show()
我希望只将年份视为x轴标签,而不是年份和季节。
我确信这样做很简单,我做错了,但我无法弄清楚是什么......
修改
更改df.plot函数稍微更好地绘制日期,但仍然是几个月,我宁愿只有一年,但这比以前略好。
新代码:
File "C:\Users\myname\AppData\Local\Continuum\Anaconda\lib\site-packages\matplotlib\dates.py", line 225, in _from_ordinalf
dt = datetime.datetime.fromordinal(ix)
ValueError: ordinal must be >= 1