Tests if the letters in a character string are uppercase.
$isupper(string)
| string | a character string or an expression that evaluates to a character string |
1-character binary string. Evaluates to 1 ($True) if string meets the validation test; otherwise, evaluates to 0 ($False).
This function tests if a particular character string is uppercase, i.e., contains no lowercase letters.
$isupper("aBC")
Evaluates to $False.
$isupper(43)
Evaluates to $True.