The question mark (?) is a quantifier in regular expressions that indicates that the preceding element should be matched zero or one time. It allows you to specify that the element is optional, meaning it may occur once or not at all. For example, ab?c will be matched for the string a...
Before you move on, you might want to play with the previous code example a little to really let the meaning of it sink in. I still remember this taking me a while to wrap my head around. So don’t worry about spending a few minutes in an interpreter session on this. It’ll be w...
\ -- inhibit the "specialness" of a character. So, for example, use \. to match a period or \\ to match a slash. If you are unsure if a character has special meaning, such as '@', you can put a slash in front of it, \@, to make sure it is treated just as a character....
^ has no special meaning if it’s not the first character in the set. To match a literal ']' inside a set, precede it with a backslash, or place it at the beginning of the set. For example, both [()[\]{}] and []()[{}] will both match a parenthesis. | A|B, where A ...
Before you move on, you might want to play with the previous code example a little to really let the meaning of it sink in. I still remember this taking me a while to wrap my head around. So don’t worry about spending a few minutes in an interpreter session on this. It’ll be ...
overlay_intersects('L1',@id,return_details:=true)(on L2) returns[ { 'id': 1, 'overlap': 4, 'radius': 1, 'result': 1 } ]: the returned overlap value is 4 units (only the area of the biggest part) while in my opinion it should be 5 units (the total area). ...
(?<=abc)def will find a match in abcdef, since the lookbehind will back up 3 characters and check if the contained pattern matches. The contained pattern must only match strings of some fixed length, meaning that abc or a|b are allowed, but a* and a{3,4} are not. Note that ...
Up in the Air-17 Wedding’s meaning. Can you believe it’s tomorrow? How are you gonna sleep? I don’t know. Well, do you want some Xanax(安眠药)? I don’t think that’s for sleeping. Yeah. No, I...Java的多线程问题,带jvm解析 Java的多线程问题 linux时间片一样 window优先级...
Meaning of TextQualified attribute in flat file connections Merge join not able to join properly on varchar column Merge Join produces wrong results when inputs are sorted with order by in the query Merge Join running for Long time in SSIS meta data in ssis Metadata could not be dertermined...
For example, supposing that we want to find lines that contain comments in Python files, we might try searching for #* . But this regex will match any line whatsoever, including blank lines because the meaning is “match any number of #s”—and that includes none. As a rule of thumb ...