how to get substrings javascript?

Question

I have a string like var str = 'Foo faa {{Question14}} {{Question23}}' . Now I want to get the substrings {{Question14}} and {{Question23}} by doing some operation on str . The digit part is variable in the str 's substrings. I need to replace these substrings with their respective ids. How can I do that?

Answer 1

This is when RegEx comes in handy.

var str = 'Foo faa {{Question14}} {{Question23}}'
var pattern = /(\{\{[a-zA-Z0-9]+\}\})/gi;
var matches = str.match(pattern);

console.log(matches[0]); //{{Question14}}
console.log(matches[1]); //{{Question23}}

Answer 2

You can do It by this way:

 var str = 'Foo faa {{Question14}} {{Question23}}', arr = str.match(/{{Question[0-9]+}}/igm); alert(arr[0]); // {{Question14}} alert(arr[1]); // {{Question23}} 

Replace matches with some IDs:

str.replace(/{{Question([0-9]+)}}/igm, "id=$1"); // "Foo faa id=14 id=23"

When the regular expression contains groups (denoted by parentheses), the matches of each group are available as $1 for the first group, $2 the second, and so on.

Answer 3

try this

 var str = 'Foo faa {{Question14}} {{Question23}}'; var replacements = { "{{Question14}}" : "Hello", "{{Question23}}" : "Hi", }; var output = str.replace(/{{\\w+}}/g, function(match){ return replacements [match] }); console.log(output);