From numbers we’ll move to alphabets first an example for validation lowercase alphabets and then to validate both uppercase and lowercase.
Yet, a developer may have an occasion where accepting formatted currency is required.
These expressions expand on and specialize from the previous examples.
A regular expression to check that would look like this: These regular expressions are similar to the three above.
The only changes are: a call to alltrim an expression covered earlier and the symbols [- ]? Decimals or floats as they are commonly called present additional considerations.
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.
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.
Once you learn the art of using regular expressions you can use it with many computer languages.