How to Check if a String is a Number Using Python

How to Check if a String is a Number Using Python

Greetings, in this Python tutorial we shall be looking at how to check if a string is a number using Python.

This is type check validation, we are validating a string by checking if it is a valid number. By valid number, we mean is the string a number. This can be an integer, float, double and more. In simple terms, we will allow for whole numbers, negative numbers and decimal numbers.

To check if a string is a number with Python, we need to ensure there is no more than 1 decimal point, left side 0 padding, no more than 1 minus symbol, and it must be at the start and not followed by a 0 and much more!

So, how can we check if a string is a number in Python? Well, we can use a regex pattern. The regex pattern is a sequence of characters that defines a search pattern. It can be used to match and manipulate strings based on specific criteria.

Python number regex used in this tutorial: r'^-?(0|[1-9]\d*)(.\d+)?$'

Here is a breakdown of what each part of the regex pattern we use in this Python tutorial:

^ asserts the start of the string.

^-? matches an optional negative sign at the beginning of the string.

(0|[1-9]\d*) matches either a single zero or a non-zero digit followed by zero or more digits.

(.\d+)? matches an optional decimal point followed by one or more digits. $ asserts the end of the string.

Thanks for watching this tutorial on how to check if a string is a number using Python.

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How to Check if a String is a Number Using Python ... https://www.youtube.com/watch?v=ET09QfjyJuc