Question

A regular expression in preg_match is given as /server\-([^\-\.\d]+)(\d+)/. Can someone help me understand what this means? I see that the string starts with server- but I dont get ([^\-\.\d]+)(\d+)'

Answer 1

Here’s the explanation:

# server\-([^\-\.\d]+)(\d+)
# 
# Match the characters “server” literally «server»
# Match the character “-” literally «\-»
# Match the regular expression below and capture its match into backreference number 1 «([^\-\.\d]+)»
#    Match a single character NOT present in the list below «[^\-\.\d]+»
#       Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
#       A - character «\-»
#       A . character «\.»
#       A single digit 0..9 «\d»
# Match the regular expression below and capture its match into backreference number 2 «(\d+)»
#    Match a single digit 0..9 «\d+»
#       Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»

You can use programs such as RegexBuddy if you intend to work with regexes and are willing to spend some funds.

You can also use this free web based explanation utility.