JQuery: replace string with regex

Question

i have a string like this:

var stringA = "id=3&staffID=4&projectID=5";

how do i use regex to replace the value of staffID=4 to staffID=10?

any help would be great

Answer 1

You want to replace staffID use following regexp pattern,

Check this Demo jsFiddle

jQuery

str = "id=3&staffID=4&projectID=5";    
str = str.replace(/staffID=\d/g, "staffID=10");  
console.log(str);

Console Result

id=3&staffID=10&projectID=5 

---

Same way you can change id, staffID and projectID using /id=(\\d+)&staffID=(\\d+)+&projectID=(\\d+)/g, REGEXP pattern ,

jQuery

str = "id=3&staffID=12&projectID=5";    
str = str.replace(/id=(\d+)&staffID=(\d+)+&projectID=(\d+)/g, "id=1&staffID=2&projectID=3");  
console.log(str);

Console Result

id=1&staffID=2&projectID=3 

Check this Demo Hope this help you!

Answer 2

Here is the simple regex you are looking for.

result = stringA.replace(/(id=\d+&staffID=)\d+(&projectID=\d+)/g, "$110$2");

Basically, the expression captures everything before the staffID into Group 1, and captures everything after the staffID into Group 2.

Then we replace the string with the Group 1 capture, concatenated with "10", concatenated with Group 2. That is the meaning of the "$110$2" replacement. The first number looks like 110, but the first 1 actually belongs to the $ ($1 means Group 1 in a replacement string).