Google Apps Script Regular Expressions

RegEx

A regular expression, also called a regex, is a method for matching text with patterns. For example, a regular expression can describe the pattern of email addresses, URLs, telephone numbers, employee identification numbers, social security numbers, or credit card numbers.

What Is a Regular Expression?

A sequence of symbols and characters expressing a string or pattern to be searched for within a longer piece of text.
When you search for data in a text, you can use this search pattern to describe what you are searching for. A regular expression can be a single character or a more complicated pattern.
Regular expressions can be used to perform all types of text search and text replace operations.

Ref Google: For additional instructions and guidelines, see also Guidelines for using regular expressions and RE2 Syntax.

Syntax

/pattern/modifiers;

var patt = /googleAppsScript/i;

/googleAppsScript/i  is a regular expression.

googleAppsScript  is a pattern (to be used in a search).

Regular Expression Modifiers

The Modifiers can be used to perform case-insensitive more global searches:

Modifier Description

i Perform case-insensitive matching

g Perform a global match (find all matches rather than stopping after the first match)

m Perform multiline matching

Using String Methods

In Google Apps Script regular expressions are often used with the two string methods: search() and replace().

The replace() method returns a modified string where the pattern is replaced.

The search() method uses an expression to search for a match and returns the position of the match.

Example

Use String replace() With a Regular Expression

function RegEx1() {
  try{
    var inputString = "This is string example....wow!!! this is really string."; 
    var outputString = inputString.replace(/ is /g, ' was ');
    Logger.log(outputString);
  }catch(ex){
  Logger.log(ex);
  }
}

// O/p: [18-04-01 11:47:31:972 IST] This was string example....wow!!! this was really string

Use String search() With a Regular Expression

function RegEx2() {

  try{

    var inputString = "Visit My Blog scriptingwithshiva"; 

    var outputString = inputString.search(/scriptingwithshiva/i);

    Logger.log(outputString);

  }catch(ex){

  Logger.log(ex);

  }

}

Log: [18-04-01 11:34:50:807 IST] 14.0

Validate email address using RegEx

function RegEx3() {
  try{
    var emailStr = "abc@gmail.com"
    var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    var isMail=re.test(emailStr);
    if(isMail==true){
    Logger.log("It is valid email ID")
    }else{
     Logger.log("It is not valid email ID")
    }
  }catch(ex){
    Logger.log(ex);
  }
}

// O/p [18-04-01 12:02:37:295 IST] It is valid email ID

Happy Coding...