python - Pandas 时间子集时间序列 - 特定时间以上的日期

Question

如果 df[:'2012-01-07'] 返回日期低于 20120107 的子 DataFrame，什么返回日期高于 20120107？ df['2012-01-07':] 没有...

Answer 1

对我来说它工作完美，但也许在实际数据中需要按 sort_index 排序索引:

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