Quote:
Originally Posted by gmaxey
'**********************************************REG EX PATTERN QUESTIONS***************************************** *****************
'1. Could we use the system separator in the pattern ?? 'oRegEx.Pattern = "^((?:\d*" & strSep & ")?\d+)(?:|\-)(US|UK|AP|BR|L).*$" _
'2. In original, the "((?:\d*\.)?\d+)"
'I understand that second "?" means the preceeing parenthetical elment (?:\d*\.) does not have to be found. _
That the \d* represents 0 or more numbers, and the \. is a literal period (or in our case decimal separator). _
But what is the purpose of "?:"
'As best I can tell from testing. The pattern can be rewritten either:
'oRegEx.Pattern = "^((\d*\.)?\d+)(?:|\-)(US|UK|AP|BR|L).*$"
'Where those two charcters just aren't used ...
'or ... use a an OR |
'oRegEx.Pattern = "^(\d*\.\d+|\d+)(?:|\-)(US|UK|AP|BR|L).*$"
'3. Similiarliy, the "(?:|\-)".
'I have deduced that signifies the "-" separating the number and region is not required.
'But, what does the "?:" and "" signify?
'As best I can tell from testing. The pattern can be rewritten:
'oRegEx.Pattern = "^((\d*\.)?\d+)(-*)(US|UK|AP|BR|L).*$"
'**********************************************END QUESTIONS***************************************** *****************
|
1. If OP uses dot in the data: 0.75-UK1234, 0.5BR, 1.25-AP, … then there will always be DOT in this data. But strSep in OP's system is DOT and on my system it is COMMA. For this it has to be DOT and not strSep.
2. Yes, except that \. is a literal period, not a decimal separator, because someone has decimal separator = DOT and I have decimal separator = COMMA.
Read about Backreferences, capturing group, non-capturing group.
a. (\w+) --> capturing group --> \1, \2, … --> $1, $2, …
you have to remember the group somewhere so that you can refer to it later (\1, $1)
b. (?:\w+) --> non-capturing group
You don't have to remember the group because you won't need it later. You can use capturing group but why.
3. (|\-) = "" OR "-"
In regEx some characters do not mean themselves, they have a different meaning. For example "." does not mean DOT but any character. If we want to use DOT we have to precede with the "" character
"." --> any character
"\." --> DOT.
I don't remember if "-" is a special character so I will use "\-". I guess you can use "-". But "\-" can be too.
"a" --> "a"
"\a" --> also "a".
Naturally:
There are many solutions to the same mathematical problem.
There are many roads that lead to Rome.
There are many patterns that mean the same thing.
