vim: how to replace something only in a column

Question

I want to replace to symbols ":" and "-" both to tab in the first column of a file:

The input is like:

chr1:100-200 1 2 3e-4
chr2:300-400 4 5 6e-4

And I want the output to be:

chr1 100 200 1 2 3e-4
chr2 300 400 4 5 6e-4

I know how to do replacement globally by "%s/:/^I/g" to replace ":" to a tab.

But because some of the entries have numbers in scientific notation such as 3e-4, I can not just use "%s/-/^I/g" to replace "-" to a tab.

Does anyone know how to specify replacement only to the first column?

Thanks.

Answer 1

You can use "Ctrl+V", active the "VISUAL BLOCK" mode, select the columns to be changed, press "c", make the change, and then "Esc", it will be applied to all selected columns.