How to parse data from an extracted JSON object property using AngularJS?

Question

I have a JSON object property that is a string and looks like this:

"&1 *UBIN 8 &2 *UBIN 8 &3 *UBIN 8 &4 *CHAR 10 &5 *UBIN 8 &6 *UBIN 8 &7 *UBIN 8 &8 *CCHAR *VARY 4"

I want to parse this property (string) to extract the numbers that have an & (ampersand) in front of them, and place each extracted &number into an array. The result would look like:

var array = ['&1', '&2', '&3', '&4', '&5', '&6', '&7', '&8'];

I am using AngularJS.

Any suggestions on how to best accomplish this?

Answer 1

try this

var str="&1 *UBIN 8 &2 *UBIN 8 &3 *UBIN 8 &4 *CHAR 10 &5 *UBIN 8 &6 *UBIN 8 &7 *UBIN 8 &8 *CCHAR *VARY 4";

var result = $.map(str.split(" "), function(element) {
  if ( element.substring(0,1)  == "&") return element;
});

result

["&1","&2","&3","&4","&5","&6","&7","&8"]

Answer 2

The algorithm for this would be "split() and filter()".

A naive approach could check if the first character is an ampersand:

input = "&1 *UBIN 8 &2 *UBIN 8 &3 *UBIN 8 &4 *CHAR 10 &5 *UBIN 8 &6 *UBIN 8 &7 *UBIN 8 &8 *CCHAR *VARY 4"

input.split(" ").filter(item => item.startsWith("&"))

This works well and is fast, but makes the assumption that only numbers can come after &, so it will also return items like &abc.

You could also use a regex:

input.split(" ").filter(item => item.match(/^&\d+$/))

This is slower, but it's more robust. It also makes the assumption that only full-number items are allowed, so it will reject items like &12a.

Both solutions can be adapted if the full list of requirements differ, as from the question is not fully clear if:

• the separator is space, or it can be other characters (e.g. comma, or newline, or tab)
• items starting with & are known to contain only numbers, or can contain other characters too
• negative numbers are considered valid or not