Dataframe 根据其他列的条件新增一列

如代码所示，判断如果城市名中含有ing字段且年份为2016，则新列test值赋为1，否则为0.

import numpy as np
import pandas as pd
 
data = {'city': ['Beijing', 'Shanghai', 'Guangzhou', 'Shenzhen', 'Hangzhou', 'Chongqing'],
       'year': [2016,2016,2015,2017,2016, 2016],
       'population': [2100, 2300, 1000, 700, 500, 500]}
frame = pd.DataFrame(data, columns = ['year', 'city', 'population', 'debt'])
 
def function(a, b):
    if 'ing' in a and b == 2016:
        return 1
    else:
        return 0
print(frame, '\n')
frame['test'] = frame.apply(lambda x: function(x.city, x.year), axis = 1)
print(frame)

 

另外Series类型也有apply函数，用法示例如下：

 

import numpy as np
import pandas as pd
 
data = {'city': ['Beijing', 'Shanghai', 'Guangzhou', 'Shenzhen', 'Hangzhou', 'Chongqing'],
       'year': [2016,2016,2015,2017,2016, 2016],
       'population': [2100, 2300, 1000, 700, 500, 500]}
frame = pd.DataFrame(data, columns = ['year', 'city', 'population', 'debt'])
 
print(frame, '\n')
frame['panduan'] = frame.city.apply(lambda x: 1 if 'ing' in x else 0)
print(frame)