For context, please check this SO post.
full script:
(get-content file.txt -ReadCount 0) -replace '([^,]")"','$1' |
set-content newfile.txt
I am specifically looking for a translation of the logic in this portion of the script:
'([^,]")"','$1' |
Can someone please either explain the logic/syntax, or point me in the right direction?
'([^,]")"' is a regular expression that matches any character except a comma followed by two consecutive double quotes. The parentheses group the first character and the first double quote.
'$1' is a back-reference to the group in the match, which in the replacement means "replace the match with just the first group", e.g. in a string foo""bar the sequence o"" would be replaced with just o", thus removing the second double quote.
| is a pipe that feeds the result of the replacement into the next cmdlet in the pipeline (Set-Content newfile.txt).
'([^,]")"','$1'
Let's break this into two pieces the regex pattern '([^,]")"' and the replacement text '$1'. The () in the regex pattern creates an unnamed capture group that is referenced in the replacement text via $1 i.e. it is the first (and only in this case) set of parens. What is matched & captured in this capture group is any character except a comma followed by a double quote that is also followed by another double quote outside of the capture group. So it eliminates one of two consecutive double quotes unless the first is preceded by a comma.
the ^ symbol matches the beginning of a string.
Great references here and here that pretty well explain everything.
Intro to Regex in Power shell here.
when the ^ symbol appears in brackets [] it will match anything not including what follows the carrot
'([^,]")"','$1' ?
^ does not match beginning of string when in a character class [...]. Inside the [] it matches a literal caret character.
[^,] means "any character except a comma".
^symbol.