正则表达式弄乱了json_decode（）;

Question

I am using a file containing a json string to create request validations. One of the slices of JSON in one of my tests looks like this:

    {
        "name": "pattern",
        "attributes": [
            {
                "name": "pattern",
                "value": "^[\d]{2}$"
            }
        ]
    }

when you try to use json_decode() on this string however, you get a json syntax error. It has something to do with the content of the regular expression. Why and is there a way around this?

Answer 1

The backslash needs to be escaped:

  "value": "^[\\d]{2}$"

JSON allows the following tokens in strings:

• any-Unicode-character-except-"-or-\-or-control-character
• \"
• \\
• \/
• \b
• \f
• \t
• \u four-hex-digits

\d is not allowed.