Question

I want to validate a text string for a specific value:

1. All numeric except for a decimal.
2. The decimal cannot be the first or last character.
3. It can have any number of digits but only one decimal.

I am trying to find a reference that will describe the mask below as it does not fit my needs.

NSString *myRegex = @"^\\d+(?:[:](?:[0-5]?\\d)|\\.\\d)$";

Please lead me to the documentation that describes the above characters.

Answer 1

That’s a regular expression.

How about:

NSString *myRegex = @"^\d+(\.\d+)?$";

Have you thought about commas, dollar signs, negative or positive signs? If those are allowed then you should probably try to parse the string as a number using an iOS library method.