Having difficulty using JavaScript regex to replace the middle of content?

Question

Having difficulty using JavaScript regex to replace the middle of content?

I am working with a text

name[one][1][two][45][text]

Through this pattern, I am able to extract the number "45"

/(.*?)rows\]\[([0-9]*)(.*)/;

Now, my challenge is how can I change the only 45 to a different digit? Using the same pattern and replace method replaces the entire previous word. Here is the code snippet:

var name = "name[one][1][two][45][text]";
var pattern = /(.*?)two\]\[([0-9]*)(.*)/;
var number = name.match(pattern);
number = parseInt(number[2]);

var replacePattern = /(.*?)two\]\[([0-9]*)/;
var newName = name.replace(replacePattern, parseInt(number + 2));
console.log(newName);

Unfortunately, the output is 47][text]

javascript regex

Answer 1

Answer №1

Is there a way to substitute the lone 45 with any different number?

You have the option to utilize the replace function with matching groups:

For instance — I swapped out the 45 with 7 here:

   "name[one][1][two][45][text]".replace(/(.*?)(two\]\[)([0-9]*)(.*)/,function (a,b,c,d,e){
        // implement your desired replacement
        return b+c+'7'+e;
    })

Output:

"name[one][3][two][7][text]"

Take note that I've included () to encompass other sections that can be added later.

Edit: in relation to your specific example (+=2) : this method can be used:

return b+c+(parseInt(d)+2)+e; -- for your exact scenario

Answer 2

Is there a way to substitute the lone 45 with any different number?

You have the option to utilize the replace function with matching groups:

For instance — I swapped out the 45 with 7 here:

   "name[one][1][two][45][text]".replace(/(.*?)(two\]\[)([0-9]*)(.*)/,function (a,b,c,d,e){
        // implement your desired replacement
        return b+c+'7'+e;
    })

Output:

"name[one][3][two][7][text]"

Take note that I've included () to encompass other sections that can be added later.

Edit: in relation to your specific example (+=2) : this method can be used:

return b+c+(parseInt(d)+2)+e; -- for your exact scenario

Answer 3

Answer №2

In the event that you can guarantee there will only be 2 numbers present, utilize the following regular expression pattern:

([0-9]+)(?!.*?\d)

Take a look at the demo for reference.

https://regex101.com/r/pL4kQ8/1

Answer 4

In the event that you can guarantee there will only be 2 numbers present, utilize the following regular expression pattern:

([0-9]+)(?!.*?\d)

Take a look at the demo for reference.

https://regex101.com/r/pL4kQ8/1

Answer 5

Answer №3

If you want to achieve this, follow these steps:

let myVar = "variable[test][1][key][23][string]";
// regex pattern to detect 2 or more digits within square brackets
let myPattern = /\[([\d]{2,})\]/;
console.log(myVar.replace(myPattern,"[47]");)

Answer 6

If you want to achieve this, follow these steps:

let myVar = "variable[test][1][key][23][string]";
// regex pattern to detect 2 or more digits within square brackets
let myPattern = /\[([\d]{2,})\]/;
console.log(myVar.replace(myPattern,"[47]");)

Answer 7

Answer №4

When using String.replace in JavaScript, you have the option to pass a function as the second argument. This function will be called for each regex match found in the string, allowing you to perform additional calculations or manipulations within that function.
By adjusting the capturing groups in the regex pattern slightly, you can achieve different outcomes. Here is an example:

name.replace(
    /((?:.*?)two\]\[)([0-9]*)(.*)/g, 
    function(match, group1, group2, group3){
        //Adding 2 to the number captured in the regex
        return group1 + (parseInt(group2) + 2) + group3;
    }
)
> "name[one][2][two][47][text]"

Check out this Regex demo

Answer 8

When using String.replace in JavaScript, you have the option to pass a function as the second argument. This function will be called for each regex match found in the string, allowing you to perform additional calculations or manipulations within that function.
By adjusting the capturing groups in the regex pattern slightly, you can achieve different outcomes. Here is an example:

name.replace(
    /((?:.*?)two\]\[)([0-9]*)(.*)/g, 
    function(match, group1, group2, group3){
        //Adding 2 to the number captured in the regex
        return group1 + (parseInt(group2) + 2) + group3;
    }
)
> "name[one][2][two][47][text]"

Check out this Regex demo

Having difficulty using JavaScript regex to replace the middle of content?

Answer №1

Answer №2

Answer №3

Answer №4

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