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Programming-Idioms

  • Ada
  • Java

Idiom #110 Check if string is blank

Set the boolean blank to true if the string s is empty, or null, or contains only whitespace ; false otherwise.

import org.apache.commons.lang3.StringUtils;
boolean blank = StringUtils.isBlank(s);

This uses external library Apache Commons Lang.
boolean blank = s == null || s.isBlank();
boolean blank = s==null || s.isBlank();

Since Java 11
boolean blank = s==null || s.strip().isEmpty();

Java 11
with Ada.Strings.Fixed;
use Ada.Strings.Fixed;
Blank := Index_Non_Blank (Str) = 0;
#include <ctype.h>
#include <stdbool.h>
bool blank = true;
for (const char *p = s; *p; p++) {
	if (!isspace(*p)) {
		blank = false;
		break;
	}
}

s has type char*
New implementation...
< > ⌨
programming-idioms.org 
boolean blank = StringUtils.isBlank(s);
boolean blank = s == null || s.isBlank();
boolean blank = s==null || s.isBlank();
boolean blank = s==null || s.strip().isEmpty();
Blank := Index_Non_Blank (Str) = 0;
bool blank = true;
for (const char *p = s; *p; p++) {
	if (!isspace(*p)) {
		blank = false;
		break;
	}
}
(blank? s)
IDENTIFICATION DIVISION.
PROGRAM-ID. blank string.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 BOOLEAN-BLANK     PIC X.
   88 BLANK          VALUE "T".
   88 NOT-BLANK      VALUE "F".
PROCEDURE DIVISION.
    IF s > SPACES
       SET BLANK     TO TRUE
    ELSE
       SET NOT-BLANK TO TRUE
    END-IF 	 	
STOP RUN.
bool blank = false;
if (s.empty() || std::all_of(s.begin(), s.end(), [](char c){return std::isspace(c);})) {
      blank = true;
}
bool blank = string.IsNullOrWhiteSpace(s);
bool blank = string.IsNullOrWhiteSpace(s);
bool blank = s.all!isSpace;
final blank = s == null || s.trim() == '';
bool blank = s?.trim()?.isEmpty ?? true;
blank = s == nil || String.length(String.trim s) == 0
Blank = string:is_empty(string:trim(S)).
blank = s == ''
blank := strings.TrimSpace(s) == ""
blank :: Bool
blank = all isSpace s
b = null (dropWhile isSpace s)
const blank = s == null || s.trim() === ''
val blank = s.isNullOrBlank()
(setf blank (not (find #\space s :test-not #'eql)))
 blank = (s == nil or #string.gsub(s, "^%s*(.-)%s*$", "%1") == 0)
BOOL blank=![s stringByTrimmingCharactersInSet:NSCharacterSet.whitespaceCharacterSet].length;
$blank = !trim($s);
$blank = (empty(trim($s));
blank := trim(s) = '';
$blank = !$s || $s=~/^\s*$/;
blank = not s or s.isspace()
blank = not s or \
        not sub(r'\s+', '', s)
blank = not s or \
        not any(x not in ws for x in s)
blank = s.nil? or s.strip.empty?
let blank = s.chars().all(|c| c.is_whitespace());
let blank = s.trim().is_empty();
val blank = Option(s).forall(_.trim.isEmpty)
(define (empty-string? s)
  (= (string-length s) 0))

(define blank (empty-string? (string-trim s)))
blank := s isAllSeparators.
Dim blank As Boolean = String.IsNullOrWhitespace(s)