Here is my sample string I'm trying to parse with PowerShell using Regex.
04/22/17 19:16:44 77.9 BATT Min: 00.0 Max: 100.0
Here is my Regex to get the digits:
'\d+\.\d'
What I'm trying to do is get the digits (77.9) before the string (BATT) exclusively. I'm able to get the 77.9 and BATT with:
(\d+\.\d)\s+BATT
I just need the number on it's own though and I'm not sure how to get the correct look ahead to do that.
A valid lookahead would be something like "match a number (lookahead which is followed by spaces, then BATT). In this example, looking for "one or more non-spaces" to get the number:
PS C:\> $s = '04/22/17 19:16:44 77.9 BATT Min: 00.0 Max: 100.0'
PS C:\> $s -match '\S+(?=\s+BATT)'
True
PS C:\> $Matches
Name Value
---- -----
0 77.9
But looking at your data, regex is overkill. It's a date, a time, a number - split it by spaces and take the third thing:
PS C:\> (-split $s)[2]
77.9
And on the topic of regex, I rather like regexes which "replace what you don't want" rather than "match what you do what", because they are a one-step operation and you don't have to deal with matches and group extraction:
PS C:\> $s -replace '.*?(\S+)\s+BATT.*', '$1'
77.9
You don't need a lookahead at all. Your (\d+\.\d)\s+BATT regex is correct, you just need to only select the first group:
$input = "04/22/17 19:16:44 77.9 BATT Min: 00.0 Max: 100.0"
$match = $input -match "(\d+\.\d)\s+BATT"
if( $match ) {
$value = $match[1]
Write-Host $value
}
Gives me this output:
77.9
