Transferring values between two columns in a pandas data frame

ghz 11hours ago ⋅ 2 views

Transferring values between two columns in a pandas data framez

I have a pandas data frame like this:

p q
0.5 0.5
0.6 0.4
0.3 0.7
0.4 0.6
0.9 0.1

So, I want to know, how can I transfer greater values to p column and vice versa for q column (Transfering smaller values to q column) like this:

p q
0.5 0.5
0.6 0.4
0.7 0.3
0.6 0.4
0.9 0.1

Answer

You can achieve this transformation in pandas by comparing the values in the p and q columns and swapping them where necessary. Specifically, you want to transfer the smaller values from the p column to the q column and vice versa. Here's how you can do that:

Steps:

  1. Create a mask where the p values are less than the q values.
  2. Use the mask to swap the values between the columns.

Here's the code to do that:

import pandas as pd

# Sample DataFrame
df = pd.DataFrame({
    'p': [0.5, 0.6, 0.3, 0.4, 0.9],
    'q': [0.5, 0.4, 0.7, 0.6, 0.1]
})

# Swap values: if p is less than q, swap them
mask = df['p'] < df['q']
df.loc[mask, ['p', 'q']] = df.loc[mask, ['q', 'p']].values

print(df)

Output:

     p    q
0  0.5  0.5
1  0.6  0.4
2  0.7  0.3
3  0.6  0.4
4  0.9  0.1

Explanation:

  • The mask df['p'] < df['q'] creates a boolean series that is True wherever the value of p is less than the corresponding value of q.
  • Using df.loc[mask, ['p', 'q']], we access the rows where the condition holds true, and we swap the values of p and q by assigning the swapped values df.loc[mask, ['q', 'p']].values.

This way, you move the smaller values from p to q and vice versa.

#py