使用函数pandas python基于来自其他列的值添加新列

Question

I have a dataframe and I want to add a new column based on some processing on an existing column.

import pandas as pd
def func_processcol(l):
     processedl=l+1
     return processedl
df = pd.DataFrame({'a':['l1','l2','l3','l4','l5','l6'],
                       'b':['1','2','2','1','2','2']})

Now I want to add a new column to dataframe by passing the values in column a . df[e]=[l1+1, ....]

Answer 1

I think you need apply :

def func_processcol(l):
     #changed `1` to string for correct output
     processedl=l + '1'
     return processedl
df = pd.DataFrame({'a':['l1','l2','l3','l4','l5','l6'],
                       'b':['1','2','2','1','2','2']})

df['c'] = df.b.apply(func_processcol)              
print (df)                       
    a  b   c
0  l1  1  11
1  l2  2  21
2  l3  2  21
3  l4  1  11
4  l5  2  21
5  l6  2  21