使用正则表达式检查PHP中的特定模式

Question

I am trying to create the following regular expression in PHP to match the following:

[2013-01-01 12:34:12.123] [USERNAME] something

I am able to get part of the first part but I am new to regex in php, any help is appreciated.

Important note: any space above could be one space or more.

(This is what I got so far)

/^[\[][0-9]{4}-[0-9]{2}-[0-9]{2}]/

I am using this tool to test that my regex match: http://www.pagecolumn.com/tool/pregtest.htm (just want to confirm that it is an okay tool).

Update: to clerify more, something could be any amount of text, white spaces above could be any amount of white spaces and USERNAME could be any amount of text as well.

Answer 1

Since your format has delimiters (the []s), you don't need the checks that the other answers provide. Instead you can simply use

\[([^\]]*)\]\s+\[([^\]]*)\]\s+(.*)

which breaks down to

\[([^\]]*)\] // Capture all non-] chars within [ and ]; this is the date
\s+ // some space
\[([^\]]*)\] // Capture all non-] chars within [ and ] again; this is USERNAME
\s+ // some space
(.*) // Capture all the text after; this is something

You can walk through this regex step-by-step using Debuggex.