PowerShell

Regular Expression with Multiple Matches and Named Capture Groups

See more Regular Expressions Examples

Demonstrates regular expressions with named capture groups and multiple matches. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

$sb = New-Object Chilkat.StringBuilder
$crlf = $true
$sb.AppendLine("Name: John Smith",$crlf)
$sb.AppendLine("Name: Jack Johnson",$crlf)
$sb.AppendLine("Name: Mary Adams",$crlf)

$($sb.GetAsString())

# We have the following string:
# Name: John Smith
# Name: Jack Johnson
# Name: Mary Adams

$pattern = "Name:\\s+(?<first>\\w+)\\s+(?<last>\\w+)"
$json = New-Object Chilkat.JsonObject
$json.EmitCompact = $false

$timeoutMs = 2000
$numMatches = $sb.RegexMatch($pattern,$json,$timeoutMs)
if ($numMatches -lt 0) {
    # Probably an error in the regular expression.
    # Suggestion: Use AI to help create and/or diagnose regular expressions.
    $($sb.LastErrorText)
    exit
}

# Examine the matches:
$($json.Emit())

# Here is the JSON showing the matches.
# Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

# {
#   "named": {
#     "first": 1,
#     "last": 2
#   },
#   "match": [
#     {
#       "group": [
#         {
#           "cap": "Name: John Smith",
#           "idx": 0,
#           "len": 16
#         },
#         {
#           "cap": "John",
#           "idx": 6,
#           "len": 4
#         },
#         {
#           "cap": "Smith",
#           "idx": 11,
#           "len": 5
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Jack Johnson",
#           "idx": 18,
#           "len": 18
#         },
#         {
#           "cap": "Jack",
#           "idx": 24,
#           "len": 4
#         },
#         {
#           "cap": "Johnson",
#           "idx": 29,
#           "len": 7
#         }
#       ]
#     },
#     {
#       "group": [
#         {
#           "cap": "Name: Mary Adams",
#           "idx": 38,
#           "len": 16
#         },
#         {
#           "cap": "Mary",
#           "idx": 44,
#           "len": 4
#         },
#         {
#           "cap": "Adams",
#           "idx": 49,
#           "len": 5
#         }
#       ]
#     }
#   ]
# }

# The capture group index is obtained by looking up the name in the JSON result.
# For example:

$idx_first = $json.IntOf("named.first")
$idx_last = $json.IntOf("named.last")

$i = 0
$matchCount = $json.SizeOfArray("match")
while ($i -lt $matchCount) {
    $("Match " + $i + 1 + ":")
    $json.I = $i

    $json.J = $idx_first
    $("first: " + $json.StringOf("match[i].group[j].cap"))

    $json.J = $idx_last
    $("first: " + $json.StringOf("match[i].group[j].cap"))

    $("")
    $i = $i + 1
}

# Output is: 

# Match 1:
# first: John
# first: Smith
# 
# Match 2:
# first: Jack
# first: Johnson
# 
# Match 3:
# first: Mary
# first: Adams