如何从JavaScript中的API字符串确定大小可变的多个子字符串

Question

I have an API call that as part of the object returns something like this:

"aaps":"1.50U\/h 0.36U(0.18|0.18) -1.07 0g"

I would like to pull two substrings out of this but the size of the substrings will vary. For example, I would like one variable to be the substring of the number that precedes the second "U". But this value will be anywhere between 0.00 and 100.99. So I can't just count on using indexof() .

As well I would like another variable to be the substring of the number that precedes the "g". This variable will have a value of anywhere between 0 and 250 so the number of characters of the substring will vary.

Answer 1

JavaScript's exec function is great for this.

var string = '1.50U\/h 0.36U(0.18|0.18) -1.07 0g';
var regex = /.+U.+(\d+\.\d{2})U.+(\d+)g/;
var match = regex.exec(string);
if (match) {
  console.log('Matches: ' + match[1] + ', ' + match[2]);
  // Matches: 0.36, 0
}

The regular expression captures the two numbers you need, and the exec function extracts them into an array. Here's what the regular expression means:

.+                         | Match one or more consecutive characters (any)
  U                        | Match the letter "U"
   .+                      | Match one or more consecutive characters (any)
     (                     | Capture the following:
      \d+                  |     One or more consecutive digits
         \.                |     The character "."
           \d{2}           |     Exactly 2 consecutive digits
                )          | End capture
                 U         | Match the letter "U"
                  .+       | Match one or more consecutive characters (any)
                    (\d+)  | Capture one or more consecutive digits
                         g | Match the letter "g"