Check if a string has no alphabets

Question

I'm trying to find whether the string has only numbers and special characters.

I tried below code but it isn't working

String text="123$%$443";
String regex = "[0-9]+";
String splChrs = "-/@#$%^&_+=()" ;
if ((text.matches(regex)) && (text.matches("[" + splChrs + "]+"))) {
  System.out.println("no alphabets");
}

what do you mean "no alphabets"? if you mean "doesn't contain letters", all you need to check is whether it contains a letter somewhere — Stultuske, Jun 03 '19 at 06:52
Your two regular expressions and the logical `&&` do *not* check `text` for containining *no* letters `[a-z]`. — , Jun 03 '19 at 06:54

score 14 · Answer 1 · answered Jun 03 '19 at 07:27

14

Just exclude using ^ the alphabetical letters:

[^a-zA-Z]+

See demo

answered Jun 03 '19 at 07:27

Ori Marko

56,308
23
131
233

1

this check must be done on all the text --> ^[^a-zA-Z]+$ – le Mandarin Jun 03 '19 at 07:50
@leMandarin but method return true when matches the whole String https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#matches(java.lang.String) – Ori Marko Jun 03 '19 at 07:55

score 6 · Answer 2 · 2019-06-03T07:09:12.797

6

If you want to check that text does not contain any letter [A-Za-z], try this:

if (!text.matches("[A-Za-z]+")) {
  System.out.println("no letters");
}

If you want to check that text contains only numbers and the given special characters, try this:

String regex = "[0-9\\-/@#$%^&_+=()]+";
if (text.matches(regex)) {
  System.out.println("no letters");
}

Note that the - must be escpade by a \ which itself must be escaped.

edited Jun 03 '19 at 07:09

answered Jun 03 '19 at 06:56

double quotes " it is also a special character how can i add it? – Harini Jun 03 '19 at 09:16
How can i add backslash \ – Harini Jun 03 '19 at 09:23
String regex="[0-9\\-/@~#$%!^&'*<>,-./:\"`;?{}|_+=()\\s]+"; i am using like this now i had to add backslash \ and square brackets [ ].How can i add it?and also tell me if i missed any special character. – Harini Jun 03 '19 at 09:33

score 2 · Answer 3 · answered Jun 03 '19 at 08:04

Here are several solutions that might work for various requirements:

Text must have no ASCII-only letters

if (text.matches("\\P{Alpha}+")) {
  System.out.println("No ASCII letters");
}

Text must have no letter from the whole BMP plane

if (text.matches("\\P{L}+")) {
  System.out.println("No Unicode letters");
}

Text must have no alphabetic chars

if (text.matches("\\P{IsAlphabetic}+")) {
  System.out.println("No alphabetic chars");
}

*Note: the IsAlphabetic class includes L, Nl (Letter number) and Other_Alphabetic categories and might be too broad, but is good if you need to check for letters and diacritics.

The String#matches method requires a full string match, hence no anchors (^/\A and $/\z) are used in the above code snippets.

score 0 · Answer 4 · answered Jun 03 '19 at 10:54

0

in java regex 'match' and 'find' are different methods.If your string just contains letters you wanna find,use 'find'.Or if your wanna match the whole string,use 'match'

answered Jun 03 '19 at 10:54

user9940960

134
4

Check if a string has no alphabets

4 Answers4