basic javascript - taking the integer value out of a string [duplicate]

Question

Well, though I searched for learning sources I could not find the exact thing I wanted. Please help to improve this post rather than down-voting so that all new learners can improve their knowledge.

lets assume there is a variable

var y = "number12";

var z ="";

1. how to make z=12 (how take only the integer value out of y string variable)
2. how to make z=number13 (adding one to "number"+12 )

Answer 1

Extract the number with a RegEx and then use parseInt to convert the string "12" to the number 12.

var y = "number12";
var x = parseInt( y.match(/\d+/) );
alert(x)

Answer 2

You may try this,

var y = "number12";
x = parseInt(y.match(/[\d\.]*/));

Answer 3

Given that: @Alex K. yes number is a constant

Simply:

var x = "number" + (+y.substr(6) + 1);

Answer 4

I agree with matthias

var input = "number12";

// define a regular expression to match your pattern
var re = /(\D+)(\d+)/;

// execute the regexp to get an array of matches
var parsed = re.exec(input);  // ['number12', 'number', '12']

// parse an integer value of the number
parsed[2] = parseInt(parsed[2], 10); // '12' ==> 12

// increment the number
parsed[2] += 1; // 12 ==> 13

// rejoin the string
input = parsed[1] + parsed[2]; // 'number' + 13 ==> 'number13'