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Doubt with regexp-meta character


 
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# 1  
Old 09-12-2010
MySQL Doubt with regexp-meta character

Hi,
I am learning reg exp a bit Smilie

Code:
Meta char info:
{n,m} Matches the preceding character at least n times but not more than m  times, for example, 'ba{2,3}b' will find 'baab' and 'baaab' but NOT  'bab' or 'baaaab'. Values are enclosed in braces (curly brackets).

Input file:
Code:
112
11112
1112
111112
1111112
11111112
111111112
1111111112

code used:
Code:
grep '11\{2,4\}2' ip.txt

I thought i will get minimum of 2 to maximum of 4.I want to get
Expected output:
Code:
1112
11112
111112

Actual output ,i got:
Code:
11112
1112
111112
1111112
11111112
111111112
1111111112

Is this correct? If yes can some one please explain me .

Thanks a lot in advance.
# 2  
Old 09-12-2010
It is not working as you expected, because regexp can also match from middle of the line to the end. So it matches like this:
Code:
11111112
111111112

To match only from the beggining of the line use:
Code:
grep '^11\{2,4\}2' ip.txt

This User Gave Thanks to bartus11 For This Post:
# 3  
Old 09-12-2010
oh! i got it now.

Last edited by dragon.1431; 09-12-2010 at 05:17 PM.. Reason: doubt is cleared.
 

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