Lua Requires Chilkat v11.1.0+

Regular Expression Replace Full Matches

See more Regular Expressions Examples

Demonstrates replacing the full matches of a regular expression.

Note: Chilkat uses PCRE2. See PCRE2 Regular Expressions
Also see: PCRE2 Performance

Lua

local chilkat = require("chilkat")

local subject = "John Anders, +_+_+ Mary Robins $$$$"
local pattern = "\\w+\\s+\\w+"

local sb = chilkat.StringBuilder.new()
sb:append(subject)

local json = chilkat.JsonObject.new()
json.emit_compact = false

local timeoutMs = 2000
local numMatches = sb:regex_match(pattern, json, timeoutMs)
if numMatches < 0 then
    -- Probably an error in the regular expression.
    -- Suggestion: Use AI to help create and/or diagnose regular expressions.
    print(sb.last_error_text)
    return
end

-- Examine the matches:
print(json:emit())

-- {
--   "match": [
--     {
--       "group": [
--         {
--           "cap": "John Anders",
--           "idx": 0,
--           "len": 11
--         }
--       ]
--     },
--     {
--       "group": [
--         {
--           "cap": "Mary Robins",
--           "idx": 19,
--           "len": 11
--         }
--       ]
--     }
--   ]
-- }

local sbTemp = chilkat.StringBuilder.new()

local i = 0
numMatches = json:size_of_array("match")
while i < numMatches do
    json.i = i

    -- The full match is always in group 0.
    sbTemp:clear()
    json:string_of_sb("match[i].group[0].cap", sbTemp)

    -- Indicate that we wish to replace the full match with it's value converted to uppercase.
    sbTemp:to_uppercase()
    json:update_sb("match[i].group[0].rep", sbTemp)

    i = i + 1
end

-- The JSON now has replacement strings:
print(json:emit())

-- {
--   "match": [
--     {
--       "group": [
--         {
--           "cap": "John Anders",
--           "idx": 0,
--           "len": 11,
--           "rep": "JOHN ANDERS"
--         }
--       ]
--     },
--     {
--       "group": [
--         {
--           "cap": "Mary Robins",
--           "idx": 19,
--           "len": 11,
--           "rep": "MARY ROBINS"
--         }
--       ]
--     }
--   ]
-- }

-- Call RegexReplace to update the StringBuilder with the replacements.
local success = sb:regex_replace(json)
if not success then
    print(sb.last_error_text)
    return
end

print("Result after doing replacements:")
print(sb:get_as_string())

-- Result after doing replacements:
-- JOHN ANDERS, +_+_+ MARY ROBINS $$$$