AppletTalk.com Java discussions newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  test a string has only alphabets [a-zA-Z]          AppletTalk.com Forum Index -> Java Help View previous topic :: View next topic   Author Message Matt Guest Posted: Sat Aug 21, 2004 3:13 pm    Post subject: test a string has only alphabets [a-zA-Z] If I want to test a string has only alphabets [a-zA-Z], there is no String API to do that. Is that true? I guess the best approach is to use reg expression. Please advise. thanks! boolean testAlphaString(String s) Back to top Paul Lutus Guest Posted: Sat Aug 21, 2004 3:20 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] Matt wrote: Quote: If I want to test a string has only alphabets [a-zA-Z], there is no String API to do that. Is that true? I guess the best approach is to use reg expression. Yes, perhaps, although there are several other approaches. Is this a part of your Java lesson? If so, why not try creating some code and post it, asking questions about a specific code example? I ask this because you don't learn how to write computer programs by asking other people to code for you. -- Paul Lutus http://www.arachnoid.com Back to top zoopy Guest Posted: Sat Aug 21, 2004 3:49 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] On 21-8-2004 17:13, Matt wrote: Quote: If I want to test a string has only alphabets [a-zA-Z], there is no String API to do that. Is that true? I guess the best approach is to use reg expression. Please advise. thanks! boolean testAlphaString(String s) There is String.matches(regex) <http://java.sun.com/j2se/1.4.2/docs/api/java/lang/String.html#matches(java.lang.String)> Then you'll have to create an appropriate reg expr, for which there are several posibilities (p{Alpha} could be part of it). -- Regards, Z. Back to top Nick Pomfret Guest Posted: Sat Aug 21, 2004 4:04 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] the String.matches is what you need. it takes one paramter which is a regular expression - use "[a-zA-Z]+" to match all characters in the alphabet. here is a test case to illustrate: import java.io.IOException; import junit.framework.TestCase; public class Test extends TestCase { public void test() { assertTrue("abcXZY".matches("[a-zA-Z]+")); assertFalse("abc3XZY".matches("[a-zA-Z]+")); } } -- * --------------------------------------------------* For feature-rich JTables visit http://www.tabletoolkit.com "Matt" <jrefactors (AT) hotmail (DOT) com> wrote Quote: If I want to test a string has only alphabets [a-zA-Z], there is no String API to do that. Is that true? I guess the best approach is to use reg expression. Please advise. thanks! boolean testAlphaString(String s) Back to top Tony Morris Guest Posted: Sun Aug 22, 2004 3:30 am    Post subject: Re: test a string has only alphabets [a-zA-Z] public static boolean isAlpha(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isAlpha(s.charAt(i))) { return false; } } return true; } -- Tony Morris http://xdweb.net/~dibblego/ Back to top zoopy Guest Posted: Sun Aug 22, 2004 6:49 am    Post subject: Re: test a string has only alphabets [a-zA-Z] On 22-8-2004 5:30, Tony Morris wrote: Quote: public static boolean isAlpha(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isAlpha(s.charAt(i))) { return false; } } return true; } Test.java:12: cannot resolve symbol symbol : method isAlpha (char) location: class java.lang.Character if(!Character.isAlpha(s.charAt(i))) ^ 1 error -- Regards, Z. Back to top Tony Morris Guest Posted: Sun Aug 22, 2004 7:20 am    Post subject: Re: test a string has only alphabets [a-zA-Z] sorry, "isLetter" public static boolean isLetter(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isLetter(s.charAt(i))) { return false; } } return true; } -- Tony Morris http://xdweb.net/~dibblego/ "zoopy" Quote: On 22-8-2004 5:30, Tony Morris wrote: public static boolean isAlpha(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isAlpha(s.charAt(i))) { return false; } } return true; } Test.java:12: cannot resolve symbol symbol : method isAlpha (char) location: class java.lang.Character if(!Character.isAlpha(s.charAt(i))) ^ 1 error -- Regards, Z. Back to top Thomas Schodt Guest Posted: Sun Aug 22, 2004 7:26 am    Post subject: Re: test a string has only alphabets [a-zA-Z] zoopy wrote: Quote: Test.java:12: cannot resolve symbol symbol : method isAlpha (char) location: class java.lang.Character if(!Character.isAlpha(s.charAt(i))) ^ Left as an exercise for OP ? OP should really read the javadoc on Character.is*() functions; what is considered "alpha" characters (aka. letters) are [A-Za-z] and a handful of non-ASCII characters. Back to top anon Guest Posted: Mon Aug 23, 2004 3:48 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] Tony Morris wrote: Quote: sorry, "isLetter" public static boolean isLetter(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isLetter(s.charAt(i))) { return false; } } return true; } Just to throw my hat in the ring on this debate... The above code is a better general-purpose solution than the new String.matches(regex) method because even now, not everyone is using JSE 1.4.x In my shop (large US bank) we're still on 1.3.x and will be for some time. Back to top anon Guest Posted: Mon Aug 23, 2004 6:38 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] Tony Morris wrote: Quote: sorry, "isLetter" public static boolean isLetter(String s) { for(int i = 0; i < s.length(); i++) { if(!Character.isLetter(s.charAt(i))) { return false; } } return true; } Also, the above code will return true if s.length()==0. Probably not the desired result. A better version IMO, which will match the result of s.matches("[a-zA-Z]+") is: public static boolean isLetter(String s) { final int n = s.length(); for (int i = 0; i < n; i++) if (!Character.isLetter(s.charAt(i))) return false; return (n > 0); } Back to top John Fereira Guest Posted: Thu Aug 26, 2004 7:28 pm    Post subject: Re: test a string has only alphabets [a-zA-Z] Thomas Schodt <spamtrap (AT) xenoc (DOT) demon.co.uk.invalid> wrote in news:cg9hqe$gh6 $1$8302bc10 (AT) news (DOT) demon.co.uk: Quote: zoopy wrote: Test.java:12: cannot resolve symbol symbol : method isAlpha (char) location: class java.lang.Character if(!Character.isAlpha(s.charAt(i))) ^ Left as an exercise for OP ? OP should really read the javadoc on Character.is*() functions; what is considered "alpha" characters (aka. letters) are [A-Za-z] and a handful of non-ASCII characters. In which case, a solution may be found using String.getBytes() and testing elements of the array against a range of decimal values. 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