问题
I need a regex to match something like
"4f0f30500be4443126002034"
and
"4f0f30500be4443126002034>4f0f31310be4443126005578"
but not like
"4f0f30500be4443126002034>4f0f31310be4443126005578>4f0f31310be4443126005579"
回答1:
Try:
^[\da-f]{24}(>[\da-f]{24})?$
[\da-f]{24} is exactly 24 characters consisting only of 0-9, a-f. The whole pattern is one such number optionally followed by a > and a second such number.
回答2:
I think you want something like:
/^[0-9a-f]{24}(>[0-9a-f]{24})?$/
That matches 24 characters in the 0-9a-f range (which matches your first string) followed by zero or one strings starting with a >, followed by 24 characters in the 0-9a-f range (which matches your second string). Here's a RegexPal for this regex.
回答3:
Don't need a regex.
str = "4f0f30500be4443126002034>4f0f31310be4443126005578"
match = str.count('>') < 2
match will be set to true for matches where there are 1 or 0 '>' in the string. Otherwise match is set to false.
来源：https://stackoverflow.com/questions/8854363/regexp-for-specific-matching-of-character-string