MongoDB RegEx not working

Question

I\'m trying to return documents that whose obsNum field starts with 1.. I have written the following RegEx to filter out those documents however, it returns all the

Answer 1

The regular expression you might try is:

^(1\.\d+)

Explanation:

• ^ Beginning of the string
• (…) Capturing parentheses: remember the match
• 1 Literal digit
• \d decimal digit
• + At least one

Answer 2

'^\s*1\.' is a string. The regex after removing backshash escaping will be ^s*1. which means, the string should start with any number of space/s followed by 1 and then any character.

You can use regex literal syntax

$regex: /^\s*1\./

or double-escape backslashes

$regex: '^\\s*1\\.'

I recommend to use literal syntax whenever possible as it is easy and less error-prone.