Convert between strings and numbers

This article uses Office Scripts to explain how to convert strings to numbers and numbers to strings, with sample code.

Difference from VBA

In VBA, when you use + with a string and a number, they’re either added as numbers or you get a type mismatch error (adding a Variant "34" and 6 gives 40).

In Office Scripts, on the other hand, when you use + with a string and a number, the number is implicitly converted to a string, and the operation is treated as string concatenation, even if the string could be converted to a number.

Implicit conversion to a string

const value1 = '150';

const value2 = 200;

// The output is "150200", not 350
console.log(value1 + value2); //150200

If numeric data is stored as a string, you need to convert its type explicitly.

Convert strings to numbers

Using the Number function

You can convert a string to a number by passing it as an argument to the Number function (don’t use new).

Sample using the Number function

const thisYear = Number('2022'); // 2022

const root2 = Number('1.4142'); // 1.4142

const notANumber = Number('Hello'); // NaN

const empty = Number(''); // 0

If the string contains characters that can’t be interpreted as a number, the result is NaN (Not a Number). Note that an empty string or a string that contains only whitespace becomes 0.

Using the parseInt function

You can also convert a string to a number with the built-in parseInt function.

Sample using parseInt

const thisYear = parseInt('2022'); // 2022

const root2 = parseInt('1.4142'); // 1

const notANumber = parseInt('Hello'); // NaN

const empty = parseInt(''); // NaN

Points to note

The parseInt function reads the string from the beginning for as long as it can be interpreted as an integer. As a result, anything after the decimal point is ignored (parseInt('-1.5') returns -1).

Also, unlike the Number function (which returns NaN), it returns 123 even if there are non-numeric characters partway through the string, as in parseInt('123abc'). To convert a string to a number that includes decimals, use the Number function or the parseFloat function.

Convert numbers to strings

Using Number.toString

To convert a number to a string, we recommend using the toString method of the Number object.

Sample using Number.toString

const thisYear = (2022).toString(); // '2022'

const pi = 3.1415;
const piText = pi.toString(); // '3.1415'

const binary = (100).toString(2); // '1100100'

If you specify a radix (2 to 36) as the argument, you get a string that represents the number in that base. For example, toString(2) returns a string that represents the number in binary.

Using the String function

You can also convert a number to a string by passing it as an argument to the String function.

Sample using the String function

const thisYear = String(2022); // '2022'

const pi = 3.1415;
const piText = String(pi); // '3.1415'