Replace last numbers from a string

Question

I have a string url with following structure:

url/inbox/g/{page_number}

I am in a situation where I need to replace {page_number} with a new value. So I need somehow to search for url/inbox/g and replace it with url/inbox/g/{new_value}.

How to use replace() function to achieve this?

is {page_number} the literal string "{page_number}" or is it an actual number? Also, when you say you need to search for url/inbox/g where are you searching for that? Is there a larger text where you need find all mentions of a URL and replace them, or is it just the URL itself you get as input? — VLAZ
– VLAZ, Commented Sep 14, 2016 at 22:09
@vlaz it is an actual number. by search, i mean the first parameter of replace function. thank you — Adib Aroui
– Adib Aroui, Commented Sep 14, 2016 at 22:10
@PM77-1, yes this seems to be the only solution since page_number is dynamic. I just don't know how to — Adib Aroui
– Adib Aroui, Commented Sep 14, 2016 at 22:13
You can also use .split() to split up the URL at / characters, replace the last element of the array, then join them back with .join(). These are all simple operations. — Barmar
– Barmar, Commented Sep 14, 2016 at 22:14

SaidbakR · Accepted Answer · 2016-09-14 22:21:29Z

1

Due to the number is the last portion of the string, you may use non regex solution using lastIndexOf and slice:

<script>
  url = 'url/inbox/g/44';
  replaceNumStr = 'Dummy';
  newVal = url.slice(0,url.lastIndexOf('/')+1);
  alert(newVal+replaceNumStr);
 </script>

Checkout this demo

answered Sep 14, 2016 at 22:21

SaidbakR

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The One and Only ChemistryBlob · Accepted Answer · 2016-09-14 22:10:42Z

1

Use a replace statement like this:

var newVal  = 'anything',
    pattern = "/url\/inbox\/g\/\d+$/",
    reg     = new RegExp(pattern, "i");
    repURL  = url.replace(reg, "url/inbox/g/" + newVal);

I am assuming url is dynamically accessed.

answered Sep 14, 2016 at 22:10

The One and Only ChemistryBlob

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1 Comment

Adib Aroui Over a year ago

Thank you, I will try to use your RegExp and feedback, thanks

larz · Accepted Answer · 2016-09-14 22:12:11Z

1

var url = "url/inbox/g/4321"
var your_number = 1234
url = url.replace(/\d+$/, your_number)

edited Sep 14, 2016 at 22:12

answered Sep 14, 2016 at 22:08

larz

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3 Comments

Pabs123 Over a year ago

that's not going to work because {page_number} is going to be a number which changes each time so it can't be hardcoded into the replace function call

Adib Aroui Over a year ago

the value of page_number is rendered served side, I don't have control of it. It can be 1 digit or more

larz Over a year ago

right, totally misread the question. my bad. that regex should be what you're looking for in my updated answer

Thomas W. · Accepted Answer · 2016-09-14 22:14:32Z

1

I would use the following regular expression : /\/\d*$/m And the replacement could be done with :

str.replace(/\/\d*$/m, "/" + n)

Where n is the new value

The regular expression says find everything that match "/" followed by 0 or more digits and which end the string. Reference

edited Sep 14, 2016 at 22:14

answered Sep 14, 2016 at 22:13

Thomas W.

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Adib Aroui Over a year ago

Thank you, I will try to use your RegExp and feedback, thanks

Xotic750 · Accepted Answer · 2016-09-14 22:17:47Z

1

Two other possibilities, not using RegExp.

const url = 'url/inbox/g/{page_number}';
const parts = url.split('/', 3);
const new_number = '{new_page_number}';
parts.push(new_number);
const new_url1 = parts.join('/');
console.log(new_url1);

const url = 'url/inbox/g/{page_number}';
const new_number = '{new_page_number}';
const new_url2 = `${url.slice(0, url.lastIndexOf('/'))}/${new_number}`;
console.log(new_url2);

answered Sep 14, 2016 at 22:17

Xotic750

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