Pandas时间子集时间序列 - 日期在特定时间之后

Question

如果 df[:'2012-01-07'] 返回的是日期在 20120107 之前的子数据帧，那么返回日期在 20120107 之后的是什么呢？df['2012-01-07':] 不会返回...

- Pat

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真的吗？它返回什么？ - Jon Clements

发布原始数据和演示代码，这对我来说运行良好。 - EdChum

Answer 1

对我来说它完美地工作，但也许在真实数据中需要通过sort_index对索引进行排序：

df = pd.DataFrame({'a':[0,1,2,5,4]}, index=pd.date_range('2012-01-05', periods=5))
print (df)

#if need ascending sorting
df = df.sort_index()
            a
2012-01-05  0
2012-01-06  1
2012-01-07  2
2012-01-08  5
2012-01-09  4

print (df[:'2012-01-07'])
            a
2012-01-05  0
2012-01-06  1
2012-01-07  2

print (df['2012-01-07':])
            a
2012-01-07  2
2012-01-08  5
2012-01-09  4

---

df = pd.DataFrame({'a':[0,1,2,5,4]}, index=pd.date_range('2012-01-05', periods=5))

#descending sorting
df = df.sort_index(ascending=False)

print (df)
            a
2012-01-09  4
2012-01-08  5
2012-01-07  2
2012-01-06  1
2012-01-05  0

print (df[:'2012-01-07'])
            a
2012-01-09  4
2012-01-08  5

print (df['2012-01-07':])
            a
2012-01-07  2
2012-01-06  1
2012-01-05  0

- jezrael