pandas 使用datetime创建一个示例DataFrame
示例
import pandas as pd
import numpy as np
np.random.seed(0)
# create an array of 5 dates starting at '2015-02-24', one per minute
rng = pd.date_range('2015-02-24', periods=5, freq='T')
df = pd.DataFrame({ 'Date': rng, 'Val': np.random.randn(len(rng)) })
print (df)
# Output:
# Date Val
# 0 2015-02-24 00:00:00 1.764052
# 1 2015-02-24 00:01:00 0.400157
# 2 2015-02-24 00:02:00 0.978738
# 3 2015-02-24 00:03:00 2.240893
# 4 2015-02-24 00:04:00 1.867558
# create an array of 5 dates starting at '2015-02-24', one per day
rng = pd.date_range('2015-02-24', periods=5, freq='D')
df = pd.DataFrame({ 'Date': rng, 'Val' : np.random.randn(len(rng))})
print (df)
# Output:
# Date Val
# 0 2015-02-24 -0.977278
# 1 2015-02-25 0.950088
# 2 2015-02-26 -0.151357
# 3 2015-02-27 -0.103219
# 4 2015-02-28 0.410599
# create an array of 5 dates starting at '2015-02-24', one every 3 years
rng = pd.date_range('2015-02-24', periods=5, freq='3A')
df = pd.DataFrame({ 'Date': rng, 'Val' : np.random.randn(len(rng))})
print (df)
# Output:
# Date Val
# 0 2015-12-31 0.144044
# 1 2018-12-31 1.454274
# 2 2021-12-31 0.761038
# 3 2024-12-31 0.121675
# 4 2027-12-31 0.443863具有DatetimeIndex以下内容的DataFrame：
import pandas as pd
import numpy as np
np.random.seed(0)
rng = pd.date_range('2015-02-24', periods=5, freq='T')
df = pd.DataFrame({ 'Val' : np.random.randn(len(rng)) }, index=rng)
print (df)
# Output:
# Val
# 2015-02-24 00:00:00 1.764052
# 2015-02-24 00:01:00 0.400157
# 2015-02-24 00:02:00 0.978738
# 2015-02-24 00:03:00 2.240893
# 2015-02-24 00:04:00 1.867558Offset-aliases为参数freq在date_range：
Alias Description B business day frequency C custom business day frequency (experimental) D calendar day frequency W weekly frequency M month end frequency BM business month end frequency CBM custom business month end frequency MS month start frequency BMS business month start frequency CBMS custom business month start frequency Q quarter end frequency BQ business quarter endfrequency QS quarter start frequency BQS business quarter start frequency A year end frequency BA business year end frequency AS year start frequency BAS business year start frequency BH business hour frequency H hourly frequency T, min minutely frequency S secondly frequency L, ms milliseconds U, us microseconds N nanoseconds