String validation using regular expressions

Question

String validation using regular expressions

Below is the code I am using to validate a string using regular expressions (RegEx):

if(!this.validate(this.form.get('Id').value)) {
  this.showErrorStatus('Enter valid ID');
  return;
}

validate(id) {
  var patt = new RegExp("^[a-zA-Z0-9.]{1,}$");
  return patt.test(id);
}

The following strings should be accepted:

santosh.jadi
santosh.jadi.others

The following strings should not be accepted:

.santosh.jadi
santosh.jadi.
santosh..jadi

Can someone please explain to me what I might be missing?

javascript regex angular validation typescript

Answer 1

Answer №1

Regular expressions used: /^[a-z]+([.-]?[a-z]+)?$/

Sample script:

let inputText = 'abc.def';
let regexPattern = /^[a-z]+([\.\-]?[a-z]+)?$/;
if (inputText.match(regexPattern)) {
  console.log("Match found!");
} else {
  console.log("No match found.");
}

We hope this example code is helpful for your understanding.

Answer 2

Regular expressions used: /^[a-z]+([.-]?[a-z]+)?$/

Sample script:

let inputText = 'abc.def';
let regexPattern = /^[a-z]+([\.\-]?[a-z]+)?$/;
if (inputText.match(regexPattern)) {
  console.log("Match found!");
} else {
  console.log("No match found.");
}

We hope this example code is helpful for your understanding.

Answer 3

Answer №2

Here is a regular expression that matches patterns like /^[a-zA-Z]+[.][a-zA-Z]+$/gm:

^                           // starting position
  [a-zA-Z]                  // matching letters
  +                         // matching 1 or more times
  [.]                       // matching a period
  [a-zA-Z]                  // matching letters
  +                         // matching 1 or more times
$                           // ending position

var rgx = /^[a-zA-Z]+[.][a-zA-Z]+$/gm

console.log(rgx.test('chris.zimmerman'))
console.log(rgx.test('.chris.zimmerman.'))
console.log(rgx.test('chris..zimmerman'))
console.log(rgx.test('ch3ris.zimmerman'))

If you need to allow multiple dots, such as in the pattern chris.w.zimmerman, you can use this regular expression: ^[a-zA-Z]+([.][a-zA-Z]+)+$

var rgx = /^[a-zA-Z]+([.][a-zA-Z]+)+$/gm

console.log(rgx.test('chris.zimmerman'))
console.log(rgx.test('chris..zimmerman.'))
console.log(rgx.test('chris.zimmerman.'))
console.log(rgx.test('chris.w.zimmerman'))

Answer 4

Here is a regular expression that matches patterns like /^[a-zA-Z]+[.][a-zA-Z]+$/gm:

^                           // starting position
  [a-zA-Z]                  // matching letters
  +                         // matching 1 or more times
  [.]                       // matching a period
  [a-zA-Z]                  // matching letters
  +                         // matching 1 or more times
$                           // ending position

var rgx = /^[a-zA-Z]+[.][a-zA-Z]+$/gm

console.log(rgx.test('chris.zimmerman'))
console.log(rgx.test('.chris.zimmerman.'))
console.log(rgx.test('chris..zimmerman'))
console.log(rgx.test('ch3ris.zimmerman'))

If you need to allow multiple dots, such as in the pattern chris.w.zimmerman, you can use this regular expression: ^[a-zA-Z]+([.][a-zA-Z]+)+$

var rgx = /^[a-zA-Z]+([.][a-zA-Z]+)+$/gm

console.log(rgx.test('chris.zimmerman'))
console.log(rgx.test('chris..zimmerman.'))
console.log(rgx.test('chris.zimmerman.'))
console.log(rgx.test('chris.w.zimmerman'))

Answer 5

Answer №3

Success! Check out the regex pattern ^[a-zA-Z]+([\.\-]?[a-zA-Z]+)+$

if(!this.validate(this.form.get('Id').value)) {
  this.showErrorStatus('Enter valid ID');
  return;
}

validate(id) {
  var guard = new RegExp("^[a-zA-Z]+([\.\-]?[a-zA-Z]+)+$");
  return guard.test(id);
}

Answer 6

Success! Check out the regex pattern ^[a-zA-Z]+([\.\-]?[a-zA-Z]+)+$

if(!this.validate(this.form.get('Id').value)) {
  this.showErrorStatus('Enter valid ID');
  return;
}

validate(id) {
  var guard = new RegExp("^[a-zA-Z]+([\.\-]?[a-zA-Z]+)+$");
  return guard.test(id);
}

String validation using regular expressions

Answer №1

Answer №2

Answer №3

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