Check if string starts with a digit
Given a string, check if the string starts with a digit, using JavaScript.
Solution
To check if given string str
starts with a digit using JavaScript, call test()
method on the regular expression /^\d/
and pass the given string as argument to the method.
/^\d/.test(str)
The test()
method returns true
if the given string str
starts with a digit, or false
otherwise. We can use this expression as a condition in if-else statement.
Program
1. Given a string str
. Check if this string starts with a digit.
var str = '24 apples';
if ( /^\d/.test(str) ) {
console.log('string starts with digit');
} else {
console.log('string does not start with digit');
}
Since the string contains digit as its first character, if-block must run.
2. Given a string str
. This string does not start with a digit. Check programmatically if this string starts with a digit.
var str = 'hello 24 apples';
if ( /^\d/.test(str) ) {
console.log('string starts with digit');
} else {
console.log('string does not start with digit');
}
Since the string does not contain digit as its first character, else-block must run.