find the first character of a word

Question

I have sentences starting with

ccccccccddkskdjskjdksjdfksjfkjs sjfsjfksjjs

I want to see if the starting of the line I read is with a number and . if yes I want to read the rest of the line.

How can I do that ?

I taught of reading the line to a

 string str.
str[0] and str [1].
str[1]= .

 x= Character.isDigit(string.charAt(0)); 
 if(x) { if (string.charAt(1)=='.') 
 { print ...I get a Exception

is there a easy way that I can check if str[0] is a number ..right now I am checking manually if it is 1 (or) 2...like that?

Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1 at java.lang.String.charAt(Unknown Source)

score 3 · Accepted Answer · answered Sep 26 '12 at 06:35

3

Character class has isDigit method, which you can use as follows:

String str1 = "I start with letter";
boolean startWithDigit = Character.isDigit(str1.charAt(0));
// startWithDigit = false

String str2 = "1 start with digit";
boolean startWithDigit = Character.isDigit(str2.charAt(0));
// startWithDigit = true

answered Sep 26 '12 at 06:35

Azodious

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Thank you this resolved by question..but I am having one more associated question before I close this: ----Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 1 at java.lang.String.charAt(Unknown Source)...I tried like you said x= Character.isDigit(string.charAt(0)); if(x) { if (line.charAt(1)=='.') { I get that Exception – The Learner Sep 26 '12 at 06:48
add the code in your question, it will be more clear to undestand. – Azodious Sep 26 '12 at 06:50
1

before accessing index, always check `if (index < line.length())` – Azodious Sep 26 '12 at 06:51

score 1 · Answer 2 · answered Sep 26 '12 at 06:38

1

String str="1. ccccccccddkskdjskjdksjdfksjfkjs sjfsjfksjjs";
char charAt = str.charAt(0);
Pattern p = Pattern.compile("\\d+");
Matcher m1 = p.matcher(""+charAt);
System.out.println(m1.matches());

answered Sep 26 '12 at 06:38

Subhrajyoti Majumder

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akaHuman · Answer 3 · 2012-09-26T07:58:39.523

1

Check for the first character's ascii value.

 char x = str.charAt(0);
 if(x >= 48 && x <= 57)
 {
     // do whatever
 }

edited Sep 26 '12 at 07:58

answered Sep 26 '12 at 06:41

akaHuman

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You can't subscript strings in Java like that – auselen Sep 26 '12 at 07:25
You can also use >= '0', <= '9'. – auselen Sep 26 '12 at 08:15

score 0 · Answer 4 · answered Sep 26 '12 at 06:34

0

You can do:

boolean isANumber = false;
try{
  Integer.parseInt(str[0]);
  isANumber = true;
}catch(Exception e) {
}

//now isANumber is true if str[0] is a number

answered Sep 26 '12 at 06:34

Arcymag

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Char.isDigit(). Wont work if OP wants to check if it's a decimal (e.g. Double.parseDouble), or if it's not in base 10 – Arcymag Sep 26 '12 at 06:39
I don't know what are you talking about. In your code you check only first character and try to parse it. So it is too much code, isDigit is enough. – apocalypse Sep 26 '12 at 07:04

score 0 · Answer 5 · edited May 23 '17 at 11:56

0

Do like this

String string="ccccccccddkskdjskjdksjdfksjfkjs sjfsjfksjjs"

Character.isDigit(string.charAt(0));

u can check ur value like this

for more detail see this one

How do I find out if first character of a string is a number?

edited May 23 '17 at 11:56

Community

1
1

answered Sep 26 '12 at 06:48

Aamirkhan

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find the first character of a word

5 Answers5