PyPackage01---Pandas15

Intro

• query in的用法
• 对 dataframe的某个列，执行正则匹配，筛选相应行

query in

import pandas as pd

df = pd.DataFrame({"x": [1, 2, 3], "y": ['ab', 'bc', 'cd']})

df.query("x in [1,2]")

	x	y
0	1	ab
1	2	bc

x_in = [2,3]
df.query('x in @x_in')

	x	y
1	2	bc
2	3	cd

正则匹配筛选

df

	x	y
0	1	ab
1	2	bc
2	3	cd

df.y.str.contains("a")

0     True
1    False
2    False
Name: y, dtype: bool

df.query("x>0 and y.str.contains('a')", engine='python')

	x	y
0	1	ab

# 匹配d结尾的字符串
df.query("x>0 and y.str.contains('d$',regex=True)", engine='python')

	x	y
2	3	cd

Ref

[1] https://pandas.pydata.org/pandas-docs/version/0.15/generated/pandas.core.strings.StringMethods.contains.html

                                2022-04-25 于南京市江宁区九龙湖 大雨