My end goal is to validate an input field. The input may be either alphabetic or numeric.
This question is related to
javascript
string
numbers
validation
If I'm not mistaken, the question requires "contains number", not "is number". So:
function hasNumber(myString) {
return /\d/.test(myString);
}
Using Regular Expressions with JavaScript. A regular expression is a special text string for describing a search pattern, which is written in the form of /pattern/modifiers where "pattern" is the regular expression itself, and "modifiers" are a series of characters indicating various options.
The character class is the most basic regex concept after a literal match. It makes one small sequence of characters match a larger set of characters. For example, [A-Z] could stand for the upper case alphabet, and \d could mean any digit.
From below example
contains_alphaNumeric « It checks for string contains either letter or number (or) both letter and number. The hyphen (-) is ignored.onlyMixOfAlphaNumeric « It checks for string contain both letters and numbers only of any sequence order.Example:
function matchExpression( str ) {
var rgularExp = {
contains_alphaNumeric : /^(?!-)(?!.*-)[A-Za-z0-9-]+(?<!-)$/,
containsNumber : /\d+/,
containsAlphabet : /[a-zA-Z]/,
onlyLetters : /^[A-Za-z]+$/,
onlyNumbers : /^[0-9]+$/,
onlyMixOfAlphaNumeric : /^([0-9]+[a-zA-Z]+|[a-zA-Z]+[0-9]+)[0-9a-zA-Z]*$/
}
var expMatch = {};
expMatch.containsNumber = rgularExp.containsNumber.test(str);
expMatch.containsAlphabet = rgularExp.containsAlphabet.test(str);
expMatch.alphaNumeric = rgularExp.contains_alphaNumeric.test(str);
expMatch.onlyNumbers = rgularExp.onlyNumbers.test(str);
expMatch.onlyLetters = rgularExp.onlyLetters.test(str);
expMatch.mixOfAlphaNumeric = rgularExp.onlyMixOfAlphaNumeric.test(str);
return expMatch;
}
// HTML Element attribute's[id, name] with dynamic values.
var id1 = "Yash", id2="777", id3= "Yash777", id4= "Yash777Image4"
id11= "image5.64", id22= "55-5.6", id33= "image_Yash", id44= "image-Yash"
id12= "_-.";
console.log( "Only Letters:\n ", matchExpression(id1) );
console.log( "Only Numbers:\n ", matchExpression(id2) );
console.log( "Only Mix of Letters and Numbers:\n ", matchExpression(id3) );
console.log( "Only Mix of Letters and Numbers:\n ", matchExpression(id4) );
console.log( "Mixed with Special symbols" );
console.log( "Letters and Numbers :\n ", matchExpression(id11) );
console.log( "Numbers [-]:\n ", matchExpression(id22) );
console.log( "Letters :\n ", matchExpression(id33) );
console.log( "Letters [-]:\n ", matchExpression(id44) );
console.log( "Only Special symbols :\n ", matchExpression(id12) );
Out put:
Only Letters:
{containsNumber: false, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: true, mixOfAlphaNumeric: false}
Only Numbers:
{containsNumber: true, containsAlphabet: false, alphaNumeric: true, onlyNumbers: true, onlyLetters: false, mixOfAlphaNumeric: false}
Only Mix of Letters and Numbers:
{containsNumber: true, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: true}
Only Mix of Letters and Numbers:
{containsNumber: true, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: true}
Mixed with Special symbols
Letters and Numbers :
{containsNumber: true, containsAlphabet: true, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Numbers [-]:
{containsNumber: true, containsAlphabet: false, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Letters :
{containsNumber: false, containsAlphabet: true, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Letters [-]:
{containsNumber: false, containsAlphabet: true, alphaNumeric: true, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
Only Special symbols :
{containsNumber: false, containsAlphabet: false, alphaNumeric: false, onlyNumbers: false, onlyLetters: false, mixOfAlphaNumeric: false}
java Pattern Matching with Regular Expressions.
You can do this using javascript. No need for Jquery or Regex
function isNumeric(n) {
return !isNaN(parseFloat(n)) && isFinite(n);
}
While implementing
var val = $('yourinputelement').val();
if(isNumeric(val)) { alert('number'); }
else { alert('not number'); }
Update: To check if a string has numbers in them, you can use regular expressions to do that
var matches = val.match(/\d+/g);
if (matches != null) {
alert('number');
}
You can also try lodash:
const isNumeric = number =>
_.isFinite(_.parseInt(number)) && !_.isNaN(_.parseInt(number))
To test if any char is a number, without overkill?, to be adapted as need.
const s = "EMA618"
function hasInt(me){
let i = 1,a = me.split(""),b = "",c = "";
a.forEach(function(e){
if (!isNaN(e)){
console.log(`CONTAIN NUMBER «${e}» AT POSITION ${a.indexOf(e)} => TOTAL COUNT ${i}`)
c += e
i++
} else {b += e}
})
console.log(`STRING IS «${b}», NUMBER IS «${c}»`)
if (i === 0){
return false
// return b
} else {
return true
// return +c
}
}
hasInt(s)We can check it by using !/[^a-zA-Z]/.test(e)
Just run snippet and check.
function handleValueChange() {
if (!/[^a-zA-Z]/.test(document.getElementById('textbox_id').value)) {
var x = document.getElementById('result');
x.innerHTML = 'String does not contain number';
} else {
var x = document.getElementById('result');
x.innerHTML = 'String does contains number';
}
}input {
padding: 5px;
}<input type="text" id="textbox_id" placeholder="Enter string here..." oninput="handleValueChange()">
<p id="result"></p>function validate(){
var re = /^[A-Za-z]+$/;
if(re.test(document.getElementById("textboxID").value))
alert('Valid Name.');
else
alert('Invalid Name.');
}
You can do this using javascript. No need for Jquery or Regex
function isNumeric(n)
{
return !isNaN(n);
}
parseInt provides integers when the string begins with the representation of an integer:
(parseInt '1a') is 1
..so perhaps:
isInteger = (s)->
s is (parseInt s).toString() and s isnt 'NaN'
(isInteger 'a') is false
(isInteger '1a') is false
(isInteger 'NaN') is false
(isInteger '-42') is true
Pardon my CoffeeScript.
This is what you need.
var hasNumber = /\d/;
hasNumber.test("ABC33SDF"); //true
hasNumber.test("ABCSDF"); //false
One way to check it is to loop through the string and return true (or false depending on what you want) when you hit a number.
function checkStringForNumbers(input){
let str = String(input);
for( let i = 0; i < str.length; i++){
console.log(str.charAt(i));
if(!isNaN(str.charAt(i))){ //if the string is a number, do the following
return true;
}
}
}
This code also helps in, "To Detect Numbers in Given String" when numbers found it stops its execution.
function hasDigitFind(_str_) {
this._code_ = 10; /*When empty string found*/
var _strArray = [];
if (_str_ !== '' || _str_ !== undefined || _str_ !== null) {
_strArray = _str_.split('');
for(var i = 0; i < _strArray.length; i++) {
if(!isNaN(parseInt(_strArray[i]))) {
this._code_ = -1;
break;
} else {
this._code_ = 1;
}
}
}
return this._code_;
}
Below code checks for same number, sequence number and reverse number sequence.
function checkNumSequnce(arrayNM2) {
inseqCounter=1;
continousSeq = 1;
decsequenceConter = 1;
var isequence = true;
for (i=0;i<arrayNM2.length-1;i++) {
j=i+1;
if (arrayNM2[i] == arrayNM2[i+1]) {
if(inseqCounter > 1 || decsequenceConter > 1){
isequence = false; break;
}
continousSeq++;
}
else if (arrayNM2[j]- arrayNM2[i] == 1) {
if(decsequenceConter > 1 || continousSeq > 1){
isequence = false; break;
}
inseqCounter++;
} else if(arrayNM2[i]- arrayNM2[j] == 1){
if(inseqCounter > 1 || continousSeq > 1){
isequence = false; break;
}
decsequenceConter++;
}else{
isequence= false;
break;
}
};
console.log("isequence: "+ isequence);
};
It's not bulletproof by any means, but it worked for my purposes and maybe it will help someone.
var value = $('input').val();
if(parseInt(value)) {
console.log(value+" is a number.");
}
else {
console.log(value+" is NaN.");
}
Source: Stackoverflow.com