How to convert string into float in JavaScript? - GeeksforGeeks

24 Jun, 2019
We can convert a string into a float in JavaScript by using some methods which are described below:
By using Type Conversion of JavaScript
By using parseFloat() Method
Method 1: In this method we will use the Type Conversion feature of JavaScript which will convert the string value into float.
Example: Below program demonstrates the above approach
<script>     // Javascript script      // to convert string    // to float value         // Function to convert     // string to float value    function convert_to_float(a) {                  // Type conversion        // of string to float        var floatValue = +(a);                  // Return float value        return floatValue;     }     //Driver code var n = "55.225";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");  var n = "-33.565";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");</script> 
Output:
Converted value = 55.225
Type of 55.225 = number
Converted value = -33.565
Type of -33.565 = number

Method 2: In this method we will use the parseFloat() method which is an inbuilt function in JavaScript that is used to accept the string and convert it into a floating point number. If the string does not contain a numeral value or If the first character of the string is not a Number then it returns NaN i.e, not a number.
Example: Below program demonstrates the above approach
<script>     // Javascript script      // to convert string    // to float value         // Function to convert     // string to float value    function convert_to_float(a) {                  // Using parseFloat() method        var floatValue = parseFloat(a);                  // Return float value        return floatValue;     }     //Driver code var n = "245.165";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");  var n = "-915.55";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");</script> 
Output:
Converted value = 245.165
Type of 245.165 = number
Converted value = -915.55
Type of -915.55 = number

Special Case: In French the float numbers are written by the use of comma (, ) as separator instead of dot(.) as separator.Example:
The value 245.67 in French is written as 245, 67

To convert French string into float in JavaScript we will first use replace() method to replace every (, ) with (.) then follow any of above described method.
Example: Below program demonstrates the above approach
<script>     // Javascript script      // to convert string    // to float value         // Function to convert     // string to float value    function convert_to_float(a) {                  // Using parseFloat() method        // and using replace() method        // to replace ', ' with '.'        var floatValue = parseFloat(a.replace(/, /, '.'));                  // Return float value        return floatValue;     }     //Driver code var n = "245, 165";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");  var n = "-915, 55";    // Call function n = convert_to_float(n);     // Print result document.write("Converted value = " +         n + "</br> Type of " + n + " = "         +typeof n + "<br>");</script> 
Output:
Converted value = 245.165
Type of 245.165 = number
Converted value = -915.55
Type of -915.55 = number

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