unable to make a regular expression using javascript
Question
I want to make a regular expression for my university registration number. I am 75% successful to make it. I'm new and i don't know how to make it. This is what i am doing.
<!DOCTYPE html>
<html>
<body>
<script>
str = "l1s10bscs"; //successfully tested
//but i want to append any 4 digits at the end of l1s10bscs
re = /[a-zA-Z]\d{1}[s|S|f|F]\d{2}[bscs]/g;
result = re.test(str);
document.write(result);
</script>
</body>
</html>
i tried this but it doesn't work.
re = /[a-zA-Z]\d{1}[s|S|f|F]\d{2}[bscs][0-9]{4}/g; // this doesn't work
3 answers
solution1
3 ACCPTED 2012-12-05 20:35:24
/[a-z]\d[sf]\d{2}bscs\d{4}/i
According to your description, this should fit.
I changed the following:
- [bscs] means "b or s or c or s" (so "b or s or c", the extra s is meaningless). You wanted just the literal four-character string "bscs"
- \\d{1} is the same as \\d - this isn't an error, but there's no reason to explicity define a character as occurring only once.
- You have a \\g flag but no \\i, so you'll match the string you're looking for multiple times inside of a larger string, but your search isn't case insensitive.
- [s|S|f|F] means "s or | or S or |..." You meant "s or S or f...", which is written [sSfF].
- Since \\i is used to make a search case insensitive, I simplified [sSfF] to [sf]
solution2
0 2012-12-05 20:35:51
The [bscs] needs to not be in square brackets: square brackets means b or s or c or s . It works without the number because it matches "l1s10b", but the next character is not a digit so looking for 4 digits fails. Try this:
re = /[a-zA-Z]\d{1}[s|S|f|F]\d{2}bscs[0-9]{4}/g;
solution3
0 2012-12-05 20:37:59
You seem to be confusing [] and () .
() creates a group, whereas [] means "match any letter from inside".
[s|S|f|F] means 's' OR '|' OR 'S' OR 'f' OR 'F' 's' OR '|' OR 'S' OR 'f' OR 'F' . That should be (s|S|f|F) or [sSfF] .
NOTE: You can use the i modifier to make it case-insensitive.
re = /[a-z]\d[sf]\d{2}bscs\d{4}/gi;
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