Loop for creating variable based on the name of other variable-CodePudding

Following is a snapshot of the data which I have

import pandas as pd
df = pd.DataFrame({
    'brand': ['Yum Yum', 'Yum Yum', 'Indomie', 'Indomie', 'Indomie'],
    'X1': [7,7,7,7,9],
    'X2': [8,9,7,5,6],
})
print(df)

I am looking for a loop that will Identify how many "X" variables I have and then based on these "X" variables, it will create 'Y' variables. In the above case, I have X1 and X2, therefore, the new variables are Y1 and Y2(please see the code below).

If I had X1, X2, and X3 variables, then, the loop would automatically create Y1= 1, Y2= 2, and Y3= 3 variables and so on.

df2 = pd.DataFrame({
    'brand': ['Yum Yum', 'Yum Yum', 'Indomie', 'Indomie', 'Indomie'],
    'X1': [7,7,7,7,9],
    'X2': [8,9,7,5,6],
    'Y1': [1,1,1,1,1],
    'Y2': [2,2,2,2,2],
})
print(df2)

I hope this is my question is clear.

P.S. I have just started to learn python today so apologies for basic questions.

Any help would be greatly appreciated. Thanks

CodePudding user response：

It's not clear which values do you want to use in your new columns, however you can try something like this:

current_columns = df.columns

for c in current_columns:
    if c[0] == 'X':
        df['y' c[1:]] = 'value for new column'

print(df.head())

CodePudding user response：

I presume you need to create new columns with values based on the previous column suffix

import pandas as pd

df = pd.DataFrame({
    'brand': ['Yum Yum', 'Yum Yum', 'Indomie', 'Indomie', 'Indomie'],
    'X1': [7,7,7,7,9],
    'X2': [8,9,7,5,6],
    'X3': [18,19,17,15,16]
})

for col in df.columns:
    if col.startswith('X'):
        df['Y' col[1:]] = int(col[1:])
print(df)

Output:

     brand  X1  X2  X3 Y1 Y2 Y3
0  Yum Yum   7   8  18  1  2  3
1  Yum Yum   7   9  19  1  2  3
2  Indomie   7   7  17  1  2  3
3  Indomie   7   5  15  1  2  3
4  Indomie   9   6  16  1  2  3