Copy values from one column to another if values equal to a certain number

Question

Could anyone show me how to copy values in the column( m/z ) to a new column if its value equals to 300 or 305? If its value doesn't equal to 300 or 305, put 0 in the new column. It should look as follows.

Answer 1

You could do:

df['300'] = 0
df['305'] = 0

df['300'][df['m/z'] == 300] = 300
df['305'][df['m/z'] == 305] = 305

But i'm sure there might be a better way haha