The third example, limiting the number of decimals, is useful for currencies.
Data representing money are generally handled as floats since it is customary to leave out formatting characters.
The metacharacters ^ and $ meaning beginning and end of string respectively excludes any characters other than specified in the pattern.
A number with leading and trailing spaces can be considered valid because conversion to numeric data will ignore the spaces.
For example if you want to validating Indian mobile numbers followed by 91, then you can use the following regx: Have worked primarily in the domain of Calling, CRM and direct advertisers services.
The third regular expression is the same as the second with the addition of that restricts the data to having 3 to 5 of the preceding character(s) in this case digits.Etc.), you see a form contains a number of fields and each one of these fields has to be filled in with specific data such as Email, Zip code, phone number and a password with specific conditions.As a developer you create a form like this and put a label beside each field to tell the user that you should enter your zip code in this field, but actually not all the users follow the labels and enter what you are waiting for, sometimes one of the users will enter a fake email address or even enter some letters that don’t refer to anything like “abcdef” as Phone number, this mistake will lead to some problems.Of course, positive and negative integers are common, and positve integers frequently omit the sign so this requires a little consideration.A valid integer value should contain only digits and possibly a leading minus or plus sign.
Regular expressions are a good way to validate text fields such as names, addresses, phone numbers, and other user information. A regular expression can easily check whether a user entered something that looks like a valid phone number.