Replace only '-' values with NaN, don't remove minus sign for negative numbers.

[rajpython]

I have '-' and some negative numbers '-2.5' in a column of data. How to replace only column values having only '-' with NaN, leaving negative numbers unchanged. Tried below didn't work.
Data[col]=Data[col].replace(to_replace='^-$', value='NaN')

[stranac]

The simplest option is probably:

if Data[col] == '-':
    Data[col] = 'NaN'

[ichabod801]

I think you need regex = True in your replace call for that to work.