Matching only the first occurrence in a line with Regex
I am completely new to regex and I would greatly appreciate any help.
The task is simple. I have a CSV file with records that read like this:
12345,67890,12345,67890
12345,67890,12345,67890
12345,67890,12345,67890
12345,67890,12345,67890
12345,67890,12345,67890
I would like to replace the first comma with a space and leave the rest of the commas intact, for every line. Is there a regex expression that will only match the first comma?
I tried this: ^.....,
. This matches the comma, however, it also matches the entire length of the string preceding the comma, so if I try to replace this with a space all of the numbers are deleted as well.
Solution 1:
The matching pattern could be:
^([^,]+),
That means
^ starts with
[^,] anything but a comma
+ repeated one or more times (use * (means zero or more) if the first field can be empty)
([^,]+) remember that part
, followed by a comma
In e.g. perl, the whole match and replace would look like:
s/^([^,]+),/\1 /
The replacement part just takes the whole thing that matched and replaces it with the first block you remembered and appends a space. The coma is "dropped" because it's not in the first capturing group.
Solution 2:
s/,/ /
This, by default (i.e. without the g
option), replaces only the first match.
Solution 3:
This should match only the first number and the comma: ^(\d{5}),
. If you'd like to gobble up everything else in the line, change the regex to this: ^(\d{5}),(.*)$