根据列中的值从 Pandas DataFrame 中选择行

import modules

import pandas as pd

Create some dummy data

创建一些虚拟数据

raw_data = {'name': ['Willard Morris', 'Al Jennings', 'Omar Mullins', 'Spencer McDaniel'],
'age': [20, 19, 22, 21],
'favorite_color': ['blue', 'blue', 'yellow', "green"],
'grade': [88, 92, 95, 70]}

df = pd.DataFrame(raw_data)
df.head()

	age	favorite_color	grade	name
0	20	blue	88	Willard Morris
1	19	blue	92	Al Jennings
2	22	yellow	95	Omar Mullins
3	21	green	70	Spencer McDaniel

 

根据列值选择行：

#To select rows whose column value equals a scalar, some_value, use ==:
df.loc[df['favorite_color'] == 'yellow']

	age	favorite_color	grade	name
2	22	yellow	95	Omar Mullins

 

选择列值在可迭代数组中的行：

#To select rows whose column value is in an iterable array, which we'll define as array, you can use isin:
array = ['yellow', 'green']
df.loc[df['favorite_color'].isin(array)]

	age	favorite_color	grade	name
2	22	yellow	95	Omar Mullins
3	21	green	70	Spencer McDaniel

 

根据多列条件选择行：

#To select a row based on multiple conditions you can use &:
array = ['yellow', 'green']
df.loc[(df['age'] == 21) & df['favorite_color'].isin(array)]

	age	favorite_color	grade	name
3	21	green	70	Spencer McDaniel

 

选择列不等于值的行：

#To select rows where a column value does not equal a value, use !=:
df.loc[df['favorite_color'] != 'yellow']

	age	favorite_color	grade	name
0	20	blue	88	Willard Morris
1	19	blue	92	Al Jennings
3	21	green	70	Spencer McDaniel

Select rows whose column value is not in an iterable array:

选择列值不在可迭代数组中的行：

#To return a rows where column value is not in an iterable array, use ~ in front of df:
array = ['yellow', 'green']
df.loc[~df['favorite_color'].isin(array)]

	age	favorite_color	grade	name
0	20	blue	88	Willard Morris
1	19	blue	92	Al Jennings