notepad++ regex search and replace

Question

I have a file with this format

Time    Temp
11:13:23    22.6
11:13:25    22.5
11:13:27    22.6
11:13:29    22.6
11:13:31    22.6
11:13:33    22.6
11:13:35    22.7

I need to replace the time with date time and add a current column.

Date/Time   Temp    Current
2018-04-13 11:13:23 22.6    0.020
2018-04-13 11:13:25 22.5    0.020
2018-04-13 11:13:27 22.6    0.020
2018-04-13 11:13:29 22.6    0.020
2018-04-13 11:13:31 22.6    0.020
2018-04-13 11:13:33 22.6    0.020

i can find the text i want replaced but I'm struggling to replace it.

Find what \d\d:\d\d:\d\d\t\d\d.\d
Replace with 2018-04-13 "$1" 0.020

I end up with

2018-04-13 "" 0.020

Please let me know what i am doing wrong thanks.

Answer 1

The problem is that you reference a value of the first capturing group with $1, but your pattern has no capturing group.

You may use your pattern or this one (almost identical to yours, note the escaped . to only match a literal dot):

\d{2}:\d{2}:\d{2}\t\d{2}\.\d

Or - if you need to only match whole lines - add line anchors:

^\d{2}:\d{2}:\d{2}\t\d{2}\.\d$

and replace with

2018-04-13\t$0\t0.020

The $0 in the replacement pattern stands for the whole match value, no need to wrap the whole pattern with a capturing group.