PHP正则表达式（包括特定于括号和任何字母/数字/符号，取决于字符串中的位置）

Question

After a few hours of experimenting with http://www.phpliveregex.com/ - I have become rather stuck. I am looking for a regular expression that would satisfy the following example criteria:

arrname = array('blackberry', 'apple', 'orange', 'mandarin');
arrname = array('****11111', '2%%%2', '3$$$$33', '444£££44');

So essentially it boils down to the following pattern:

[arrname = array('] [any characters] [', '] [any characters] [', '] [any characters] [', '] [any characters] [');]

Where any character is literally any (letter / number / symbol) - in any order (but requires a length of at least 1 character) - hence the need for a regular expression using the preg_match() function.

My trouble is making the regular expression match the pattern stated above (repeated below).

[arrname = array('] [any characters] [', '] [any characters] [', '] [any characters] [', '] [any characters] [');]

---

UPDATE:

Having tried to implement preg_match() I've failed and am obviously missing something really stupid (errors listed below). Any idea's?

First (using double quotes on the expression)

$pattern = "arrname = array\('([^']+)', '([^']+)', '([^']+)', '([^']+)'\);";
preg_match($pattern, $data, $matches);

Gives me the error Warning: preg_match(): Delimiter must not be alphanumeric or backslash

Second (using single quote on the expression)

$pattern = 'arrname = array\('([^']+)', '([^']+)', '([^']+)', '([^']+)'\);';
preg_match($pattern, $data, $matches);

Gives me the error Parse error: syntax error, unexpected '('

Answer 1

As an aside comment, I will describe regex engine behaviour with two different patterns step by step. Keep in mind that this is only a short representation, in real life strings are processed character by character. The goal of this is to see the regex engine road.

string: arr = array('cherry', 'apple');

pattern 1: arr = array\('(.+)', '(.+)'\);

1 | arr = array('cherry', 'apple');  | arr = array\('
2 | arr = array('cherry', 'apple');| arr = array\('(.+)

Since there is no ' after the ;, the regex engine must backtrack character by character to find a match. For each backtrack position the end of the pattern is tested. This is reason why I count each backtrack position as a step.

3 | arr = array('cherry', 'apple');| arr = array\('(.+)
4 | arr = array('cherry', 'apple');| arr = array\('(.+)
5 | arr = array('cherry', 'apple');| arr = array\('(.+)

The ' is found, the regex engine stop to backtrack and continue

6 | arr = array('cherry', 'apple');| arr = array\('(.+)',

There's no , after the ' the RE restart backtracking to find another '

7 | arr = array('cherry', 'apple');| arr = array\('(.+)
...
13 | arr = array('cherry', 'apple');| arr = array\('(.+)

another ' is found

14 | arr = array('cherry', 'apple');| arr = array\('(.+)'

but not followed by a , too

15 | arr = array('cherry', 'apple');| arr = array\('(.+)
16 | arr = array('cherry', 'apple');| arr = array\('(.+)
17 | arr = array('cherry', 'apple');| arr = array\('(.+)

another ' is found followed by a , '

18 | arr = array('cherry', 'apple');| arr = array\('(.+)', '
19 | arr = array('cherry', 'apple');| arr = array\('(.+)', '(.+)

There is no ' after the ;, ...

20 | arr = array('cherry', 'apple');| arr = array\('(.+)', '(.+)
21 | arr = array('cherry', 'apple');| arr = array\('(.+)', '(.+)
22 | arr = array('cherry', 'apple');| arr = array\('(.+)', '(.+)

The ' is found, followed by all the literals at the end of the pattern

23 | arr = array('cherry', 'apple');| arr = array\('(.+)', '(.+)'\);

pattern 2: arr = array\('([^']+)', '([^']+)'\);

1 | arr = array('cherry', 'apple');  | arr = array\('
2 | arr = array('cherry', 'apple'); | arr = array\('([^']+)

Now the regex engine is forced to stop before the ' since the character class contains all characters except the '

3 | arr = array('cherry', 'apple'); | arr = array\('([^']+)', '
4 | arr = array('cherry', 'apple'); | arr = array\('([^']+)', '([^']+)

The RE stop before the ' for the same reason

5 | arr = array('cherry', 'apple'); | arr = array\('([^']+)', '([^']+)'\);