Java - Extract text from a string with a common length and prefix

Question

I have a text string "9926 9928 9951 9953 0 30 57 12 40 54 30"

I'm interested in 4-digit digits with the prefix 99. Other numbers are redundant.

Output Required:

9926
9928
9951
9953

My code is:

String str = " 9926 9928 9951 9953 0 30 57 12 40 54 30";
Iterable<String> result = Splitter.onPattern("99").fixedLength(4).split(str);

Actual output:

992
6 99
28 9
951 
9953
 0 3
0 57
 12 
40 5
4 30

Answer 1

Use Matcherwith regex 99\d{2}:

String str = " 9926 9928 9951 9953 0 30 57 12 40 54 30";

Matcher m = Pattern.compile("99\\d{2}").matcher(str);

while (m.find())
    System.out.println(m.group());

9926
9928
9951
9953

See also: Pattern

, \d , [0-9]. , {2} , ", , ". , 99\d{2} 9, :

Debuggex

, Pattern static final, , .

Answer 2

, .

• whitespace.
• . 4, , .
• 2 "99", startsWith(), , .
• ( 3) .
• , .
• /, .