Replace

Last update:

May 18, 2026

Description

Replaces occurrences of a string in a given string with either another string or the result of a callback function. Replaces the first occurrence by default, or can replace all. The search is case-sensitive. See ReplaceNoCase to perform case-insensitive searching.

Returns

The string, after making replacements.

Function syntax

Replace(string, searchstring, replacestring|obj [, scope ][,start])

History

ColdFusion (2021 release):

Added the parameter start.
Also, callback support is added.

Parameters

Parameter	Description
string	A string or a variable that contains one. String in which to search.
searchstring	A string or a variable that contains one. String to search.
obj	Replacement string (or a variable that contains one) or a callback function that returns the replacement string. You can pass the callback function in this argument. function(transform,position,original) {...}
scope	one: replaces the first occurrence (default) all: replaces all occurrences
start	Position to start searching in the string (defaults to 1).

Usage

To remove a string, specify the empty string ("") as substring2. You do not need to escape comma characters in strings. For example, the following code deletes the commas from the sentence:

replace("The quick brown fox jumped over the lazy cow, dog, and cat.",",","","All")

Example

<cfoutput>#replace("The quick brown fox","o","cf","all")#</cfoutput>

The code produces the following output:

The quick brcfwn fcfx

Example 1

Example with callback function

<cfscript>

    myStr="The quick brown fox jumped over the brown dog";

    outStr = replace( myStr, "brown", function (transform, position, original){

        return UCase(transform);

    }, "all");

    writeoutput(outStr);

</cfscript>

Output

The quick BROWN fox jumped over the BROWN dog

Example 2

<cfscript> 

  // Define the callback function 

  callback=(regexp,position,original)=>{ 

    retString = regExp.reverse()&"aze" 

    return retString 

  } 

  baseStr="The quick brown fox jumped over the lazy cow." 

  writeOutput(replace(baseStr, "ow", callback, "all", len("The quick bro"))  & "<br>") 

  writeOutput(replace(baseStr, "ow", callback, "all", len("The quick brown"))  & "<br>") 

</cfscript>

Output

The quick brwoazen fox jumped over the lazy cwoaze.

The quick brown fox jumped over the lazy cwoaze.

Note:

Usage

To remove a string, specify the empty string ("") as substring2. You do not need to escape comma characters in strings. For example, the following code deletes the commas from the sentence:

replace("The quick brown fox jumped over the lazy cow, dog, and cat.",",","","All")

Example

<cfoutput>

    #replace("The quick brown fox","fox","dog")#

</cfoutput>

The code produces the following output:

The quick brown dog

Example- usage of "all"

<cfoutput>

    #replace("The quick brown fox jumped over the brown dog","brown","black")#

</cfoutput>

Output

The quick black fox jumped over the brown dog

You can't use this replace to change "the" to "a" because replace is case-sensitive.

Real-world use cases of the Replace function

Data sanitization and cleaning

Clean and sanitize user input data for storage and display. Remove unwanted characters, normalize data formats, and ensure data consistency.

<cfscript>

    writeOutput("<h2>1. Data Sanitization & Cleansing</h2>");

    // Sample user input data that needs cleaning

    userInputs = [

        {field: "Phone Number", rawData: "(555) 123-4567 ext. 890", description: "Remove formatting for storage"},

        {field: "Social Security", rawData: "123-45-6789", description: "Remove dashes for database storage"},

        {field: "Credit Card", rawData: "4111-1111-1111-1111", description: "Remove dashes and spaces"},

        {field: "ZIP Code", rawData: "12345-6789", description: "Extract 5-digit ZIP"},

        {field: "User Comment", rawData: "This is <script>alert('hack')</script> great!", description: "Remove dangerous HTML/JS"}

    ];

    writeOutput("<h3>Input Data Sanitization Examples</h3>");

    writeOutput("<table border='1' cellpadding='8'>");

    writeOutput("<tr><th>Field Type</th><th>Raw Input</th><th>Sanitized Output</th><th>Method Used</th><th>Business Purpose</th></tr>");

    for (input in userInputs) {

        sanitizedData = "";

        method = "";

        switch (input.field) {

            case "Phone Number":

                // Remove all non-numeric characters for storage

                sanitizedData = replace(input.rawData, "(", "", "all");

                sanitizedData = replace(sanitizedData, ")", "", "all");

                sanitizedData = replace(sanitizedData, "-", "", "all");

                sanitizedData = replace(sanitizedData, " ", "", "all");

                sanitizedData = replace(sanitizedData, "ext.", "", "all");

                method = "Multiple Replace calls to remove formatting";

                break;

            case "Social Security":

                // Remove dashes for database storage

                sanitizedData = replace(input.rawData, "-", "", "all");

                method = "Replace dashes with empty string";

                break;

            case "Credit Card":

                // Remove dashes and spaces, keep only numbers

                sanitizedData = replace(input.rawData, "-", "", "all");

                sanitizedData = replace(sanitizedData, " ", "", "all");

                method = "Remove separators for secure storage";

                break;

            case "ZIP Code":

                // Extract 5-digit ZIP (remove extended part)

                if (find("-", input.rawData)) {

                    sanitizedData = left(input.rawData, find("-", input.rawData) - 1);

                } else {

                    sanitizedData = input.rawData;

                }

                method = "Extract base ZIP code";

                break;

            case "User Comment":

                // Remove dangerous HTML/JavaScript tags

                sanitizedData = replace(input.rawData, "<script>", "", "all");

                sanitizedData = replace(sanitizedData, "</script>", "", "all");

                sanitizedData = replace(sanitizedData, "<", "&lt;", "all");

                sanitizedData = replace(sanitizedData, ">", "&gt;", "all");

                method = "XSS prevention via HTML encoding";

                break;

        }

        writeOutput("<tr>");

        writeOutput("<td><strong>" & input.field & "</strong></td>");

        writeOutput("<td>" & encodeForHTML(input.rawData) & "</td>");

        writeOutput("<td><strong>" & encodeForHTML(sanitizedData) & "</strong></td>");

        writeOutput("<td>" & method & "</td>");

        writeOutput("<td>" & input.description & "</td>");

        writeOutput("</tr>");

    }

    writeOutput("</table><br>");

    // Advanced sanitization with callback functions (ColdFusion 2021+)

    writeOutput("<h3>Advanced Sanitization with Callback Functions</h3>");

    // Example: Normalize phone numbers using callback

    phoneNumbers = ["(555) 123-4567", "555.123.4567", "555 123 4567", "+1-555-123-4567"];

    writeOutput("<table border='1' cellpadding='8'>");

    writeOutput("<tr><th>Original Phone</th><th>Normalized Phone</th><th>Formatted Display</th></tr>");

    for (phone in phoneNumbers) {

        // First clean the phone number

        cleanPhone = replace(phone, "(", "", "all");

        cleanPhone = replace(cleanPhone, ")", "", "all");

        cleanPhone = replace(cleanPhone, "-", "", "all");

        cleanPhone = replace(cleanPhone, ".", "", "all");

        cleanPhone = replace(cleanPhone, " ", "", "all");

        cleanPhone = replace(cleanPhone, "+1", "", "all");

        // Format for display

        if (len(cleanPhone) == 10) {

            formattedPhone = "(" & left(cleanPhone, 3) & ") " & 

                           mid(cleanPhone, 4, 3) & "-" & 

                           right(cleanPhone, 4);

        } else {

            formattedPhone = cleanPhone;

        }

        writeOutput("<tr>");

        writeOutput("<td>" & phone & "</td>");

        writeOutput("<td>" & cleanPhone & "</td>");

        writeOutput("<td><strong>" & formattedPhone & "</strong></td>");

        writeOutput("</tr>");

    }

    writeOutput("</table><br>");

</cfscript>

Simple templates

Replace placeholders in templates with real data.

<cfscript>

    writeOutput("<hr><h2>2. Simple Templates</h2>");

    // Example 1: Simple email template

    emailTemplate = "Hello {{NAME}}, your order total is ${{AMOUNT}}. Thank you!";

    // Replace placeholders with actual data

    customerName = "John Smith";

    orderAmount = "25.99";

    personalizedEmail = replace(emailTemplate, "{{NAME}}", customerName, "all");

    personalizedEmail = replace(personalizedEmail, "{{AMOUNT}}", orderAmount, "all");

    writeOutput("<h3>Email Template Example</h3>");

    writeOutput("<p><strong>Template:</strong> " & emailTemplate & "</p>");

    writeOutput("<p><strong>Result:</strong> " & personalizedEmail & "</p><br>");

    // Example 2: Simple form letter

    letter = "Dear {{TITLE}} {{LASTNAME}}, your appointment is on {{DATE}} at {{TIME}}.";

    title = "Mr.";

    lastName = "Johnson";

    appointmentDate = "March 15, 2024";

    appointmentTime = "2:00 PM";

    finalLetter = replace(letter, "{{TITLE}}", title, "all");

    finalLetter = replace(finalLetter, "{{LASTNAME}}", lastName, "all");

    finalLetter = replace(finalLetter, "{{DATE}}", appointmentDate, "all");

    finalLetter = replace(finalLetter, "{{TIME}}", appointmentTime, "all");

    writeOutput("<h3>Form Letter Example</h3>");

    writeOutput("<p><strong>Template:</strong> " & letter & "</p>");

    writeOutput("<p><strong>Result:</strong> " & finalLetter & "</p><br>");

    // Example 3: Simple HTML template

    htmlTemplate = "<h1>Welcome {{USER}}!</h1><p>You have {{COUNT}} new messages.</p>";

    userName = "Sarah";

    messageCount = "3";

    finalHTML = replace(htmlTemplate, "{{USER}}", userName, "all");

    finalHTML = replace(finalHTML, "{{COUNT}}", messageCount, "all");

    writeOutput("<h3>HTML Template Example</h3>");

    writeOutput("<p><strong>Template:</strong> " & encodeforHTML(htmlTemplate) & "</p>");

    writeOutput("<p><strong>Result:</strong> " & finalHTML & "</p>");

</cfscript>

Cleaning up text

Remove unwanted characters and fix formatting.

<cfscript>

    writeOutput("<hr><h2>3. Cleaning Up Text</h2>");

    // Example 1: Fix URLs with double slashes

    messyURL = "https://example.com//products//items//details/";

    cleanURL = replace(messyURL, "//", "/", "all");

    // Fix the protocol part that got broken

    cleanURL = replace(cleanURL, "https:/", "https://");

    writeOutput("<h3>Fix Double Slashes in URLs</h3>");

    writeOutput("<p><strong>Messy URL:</strong> " & messyURL & "</p>");

    writeOutput("<p><strong>Clean URL:</strong> " & cleanURL & "</p><br>");

    // Example 2: Convert file paths

    windowsPath = "C:\Users\John\Documents\file.txt";

    webPath = replace(windowsPath, "\", "/", "all");

    writeOutput("<h3>Convert Windows Paths</h3>");

    writeOutput("<p><strong>Windows Path:</strong> " & windowsPath & "</p>");

    writeOutput("<p><strong>Web Path:</strong> " & webPath & "</p><br>");

    // Example 3: Clean up user input

    userInput = "Hello!!!   How are you???   ";

    cleaned = replace(userInput, "!!!", "!", "all");

    cleaned = replace(cleaned, "???", "?", "all");

    cleaned = trim(cleaned);

    writeOutput("<h3>Clean User Input</h3>");

    writeOutput("<p><strong>Original:</strong> '" & userInput & "'</p>");

    writeOutput("<p><strong>Cleaned:</strong> '" & cleaned & "'</p><br>");

    // Example 4: Format text for display

    rawText = "price:$25.99|qty:2|total:$51.98";

    formatted = replace(rawText, "|", " • ", "all");

    formatted = replace(formatted, ":", ": ", "all");

    writeOutput("<h3>Format Text for Display</h3>");

    writeOutput("<p><strong>Raw Data:</strong> " & rawText & "</p>");

    writeOutput("<p><strong>Formatted:</strong> " & formatted & "</p>");

</cfscript>

Simple word replacement

Replace words to change meaning or fix typos.

<cfscript>

    writeOutput("<hr><h2>4. Simple Word Replacement</h2>");

    // Example 1: Fix common typos

    textWithTypos = "The recieve was good, but I definately prefer the original.";

    fixed = replace(textWithTypos, "recieve", "receive");

    fixed = replace(fixed, "definately", "definitely");

    writeOutput("<h3>Fix Typos</h3>");

    writeOutput("<p><strong>With typos:</strong> " & textWithTypos & "</p>");

    writeOutput("<p><strong>Fixed:</strong> " & fixed & "</p><br>");

    // Example 2: Change gender pronouns

    story = "He went to his car and drove to his house.";

    changed = replace(story, "He", "She", "all");

    changed = replace(changed, "his", "her", "all");

    writeOutput("<h3>Change Pronouns</h3>");

    writeOutput("<p><strong>Original:</strong> " & story & "</p>");

    writeOutput("<p><strong>Changed:</strong> " & changed & "</p><br>");

    // Example 3: Replace technical terms with simple words

    technical = "The algorithm will optimize the performance of your system.";

    simple = replace(technical, "algorithm", "program");

    simple = replace(simple, "optimize", "improve");

    writeOutput("<h3>Simplify Technical Terms</h3>");

    writeOutput("<p><strong>Technical:</strong> " & technical & "</p>");

    writeOutput("<p><strong>Simple:</strong> " & simple & "</p><br>");

    // Example 4: Change brand names

    text = "I use Google for search and Google Drive for storage.";

    generic = replace(text, "Google", "a search engine", "one");

    generic = replace(generic, "Google Drive", "cloud storage");

    writeOutput("<h3>Make Text Generic</h3>");

    writeOutput("<p><strong>Branded:</strong> " & text & "</p>");

    writeOutput("<p><strong>Generic:</strong> " & generic & "</p>");

    writeOutput("<p><em>Notice 'one' parameter replaced only first 'Google'</em></p>");

</cfscript>

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