Contains returns true, if the specified slice contains the specified element, false otherwise.

GetOnlyLetters returns a string containing only letters from given string.

GetOnlyNumbers returns a string containing only numbers from given string.

GetSignedNumbers returns a string containing only positive and negative numbers from given string.

HasLetters returns true when string contains a letter [a-zA-Z].

HasNumbers returns true when string contains a letter [0-9].

HasOnlyLetters returns true when string contains only letters.

HasOnlyNumbers returns true when string contains only numbers.