Notepad++ Regex to replace the 4th character of each line in a text file.

Question

I have a large text file and want to replace the 4th character of each line. Cloud you please suggest a Regex to do that in Notepad++?

Answer 1

An alternate to replacing with find-replace is simply to mark every 4th character by setting your cursor on the 4th character in the first line, hold down SHIFT & ALT and then pressing the down button.

This will select 4th the character on every as a column.

Answer 2

search for ^(.{3}).(.*)
replace with \1a\2

Be sure to turn off the . match multiline.
This is untested; check if it does what you need. If you say more about the structure of your document; I may come up with a better regexp.

Answer 3

If you want to replace the character at the 4th position with X, press Ctrl+H and select Regular expression as the Search Mode and use any of the these:

• Find what: ^(...)(.)
  Replace with: \1X

• Find what: ^(.{3})(.)(.*)$
  Replace with: \1X\3

• Find what: ^(.{3})(.)
  Replace with: \1X

An alternative solution for smaller files

Hold down Alt and with your mouse, drag over and select the column of text you want replaced.

You can also do this with just the keyboard by holding down Alt+Shift and then selecting the column of text you want to replace using arrow keys and then typing over it.