PHP和正则表达式：检查字符串是否遵循带方括号的模式

Question

I have no experience with regular expressions whatsoever, hence my question.

I have a string which should look like this:

[1,24,2,59]

As the string can be manipulated by the user and hence changed, I want to check whether it is still following the same organization pattern, and only containing numbers,square brackets and commas.

Answer 1

You can use this regex in preg_match to validate your input:

'/\[\d+(,\d+)*\]/'

\[ matches the character [ literally
\d+ match a digit [0-9]
Quantifier: Between one and unlimited times, as many times as possible, giving back as
  needed [greedy]
1st Capturing group (,\d+)*
Quantifier: Between zero and unlimited times, as many times as possible, giving back as 
  needed [greedy]
Note: A repeated capturing group will only capture the last iteration. Put a capturing 
  group around the repeated group to capture all iterations or use a non-capturing group 
   instead if you're not interested in the data
, matches the character , literally
\d+ match a digit [0-9]
Quantifier: Between one and unlimited times, as many times as possible, giving back as 
  needed [greedy]
\] matches the character ] literally