TypeScript parseFloat()

In this chapter, we will explore the parseFloat() function in TypeScript. This function parses a string argument and returns a floating-point number. Understanding how to use parseFloat() is useful for converting strings to floating-point numbers, especially when working with user inputs or data that may come in string format.

Table of Contents

1. Definition
2. Syntax
3. Examples
4. Conclusion

1. Definition

The parseFloat() function parses a string argument and returns a floating-point number. If the first character of the string cannot be converted to a number, it returns NaN.

2. Syntax

parseFloat(string);

Parameters

• string: The value to parse. If string is not a string, it is converted to one. Leading whitespace in the string is ignored.

Return Value

The function returns a floating-point number parsed from the given string. If the first character cannot be converted to a number, it returns NaN.

3. Examples

Let's look at some examples to understand how parseFloat() works in TypeScript.

Example 1: Basic Usage

In this example, we use parseFloat() to convert a string to a floating-point number.

let numStr: string = "42.56";
let num = parseFloat(numStr);
console.log(num); // Output: 42.56

Example 2: Handling Leading and Trailing Whitespace

In this example, we use parseFloat() to parse a string with leading and trailing whitespace.

let numStr: string = "  42.56  ";
let num = parseFloat(numStr);
console.log(num); // Output: 42.56

Example 3: Handling Non-Numeric Characters

In this example, we use parseFloat() to parse a string with non-numeric characters.

let numStr: string = "42.56abc";
let num = parseFloat(numStr);
console.log(num); // Output: 42.56

Example 4: Parsing Invalid Strings

In this example, we use parseFloat() to parse an invalid string.

let invalidStr: string = "abc";
let num = parseFloat(invalidStr);
console.log(num); // Output: NaN

Example 5: Parsing Integer Strings

In this example, we use parseFloat() to parse an integer string.

let numStr: string = "42";
let num = parseFloat(numStr);
console.log(num); // Output: 42

Example 6: Parsing Scientific Notation

In this example, we use parseFloat() to parse a string in scientific notation.

let numStr: string = "4.2e2";
let num = parseFloat(numStr);
console.log(num); // Output: 420

Example 7: Using parseFloat() with Variables

In this example, we use parseFloat() with a variable to convert a string to a floating-point number.

let str: string = "123.45";
let num = parseFloat(str);
console.log(num); // Output: 123.45

4. Conclusion

In this chapter, we explored the parseFloat() function in TypeScript, which is used to parse a string argument and return a floating-point number. We covered its definition, syntax, parameters, return value, and provided several examples to demonstrate its usage. Understanding how to use parseFloat() effectively is essential for converting strings to floating-point numbers, especially when working with user inputs or data that may come in string format.