Python 循环遍历 DataFrame 和字典

Question

I have one data frame that looks like the below

0   1   2
A   X   +2
B   Y   +3
C   Z   +1+2

And a dictionary that looks like the below

    dict = { "1":"A", "2":"B", "3":"C", }

I am trying to loop through to create the below (effectively looking up the letter from the dictionary and replacing the number in the data frame with the correct letter while keeping the "+"s )

    0   1   2
    A   X   +B
    B   Y   +C
    C   Z   +A+B

Any pointers would be much appreciated!

Answer 1

You could use replace :

import pandas as pd

d = {"1": "A", "2": "B", "3": "C", }

data = [['A',  'X', '+2'],
        ['B',  'Y', '+3'],
        ['C',  'Z', '+1+2']]

df = pd.DataFrame(data=data)

df[2] = df[2].str.replace('\d+', lambda x: d[x.group()])

print(df)

Output

   0  1     2
0  A  X    +B
1  B  Y    +C
2  C  Z  +A+B

Answer 2

You can split and join on the + character (below is where the dictionary variable is d ):

df['2'] = df['2'].apply(lambda s: '+'.join(d.get(n, "") 
                                           for n in s.split('+')))
>>> df
   0  1     2
0  A  X    +B
1  B  Y    +C
2  C  Z  +A+B