Remove a given value from a string along with comma in Javascript

Question

I am trying to remove a set of given values from a string of comma separated values as follows:

// mainString

mainString = '1,2,3,4,5'

// Values to subtracted from mainString

givenValuesString1 = '1'

givenValuesString2 = '2,3'

givenValuesString3 = '5'

givenValuesString4 = '3,5'

// Desired Output Values

desiredOutput1 = '2,3,4,5'

desiredOutput2 = '1,4,5'

desiredOutput3 = '1,2,3,4'

desiredOutput4 = '1,2,4'

What I tried is this:

desiredOutput =  mainString.replace(givenValuesString, '')

desiredOutput =  mainString.replace(`${givenValuesString},`, '')

My problem is that when I try the second method, value without a comma after it is not deleted ie, the last character in the mainString. Another problem is I am not able to delete the values if they are one after another ie, values like 2,4 or 3,5 .

Values remaining if I use the above two methods:

// First method

desiredOutput1 = ',2,3,4,5'

desiredOutput2 = '1,,4,5'

desiredOutput3 = '1,2,3,4,'

desiredOutput4 = '1,2,3,4,5'

// Second method

desiredOutput1 = '2,3,4,5'

desiredOutput2 = '1,4,5'

desiredOutput3 = '1,2,3,4,5'

desiredOutput4 = '1,2,3,4,5'

So how can I achieve the desired result? ie, the given values along with the comma must be deleted from the mainString and also even if they are not adjacent to each other.

Answer 1

Just use a Map or Set to do it. If you want order, then Map . Otherwise Set . Since you mentioned you don't need the order, I have used Set to do it.

 mainString = '1,2,3,4,5' givenValuesString1 = '1' givenValuesString2 = '2,3' givenValuesString3 = '5' givenValuesString4 = '3,5' function subtract(main, s) { let set = new Set(main.split(",").map(a => Number(a))); s.split(",").map(a => Number(a)).forEach(a => set.delete(a)) return Array.from(set).join(",") } console.log(subtract(mainString, givenValuesString1)); console.log(subtract(mainString, givenValuesString2)); console.log(subtract(mainString, givenValuesString3)); console.log(subtract(mainString, givenValuesString4));

Actually, even if using Set , if you don't do a set1 - set2 kind of operation, you can keep the order:

 mainString = '1,2,3,4,5' givenValuesString1 = '1' givenValuesString2 = '2,3' givenValuesString3 = '5' givenValuesString4 = '3,5' function subtract(main, s) { let set = new Set(s.split(",").map(a => Number(a))); return main.split(",").filter(a => !set.has(Number(a))).join(",") } console.log(subtract(mainString, givenValuesString1)); console.log(subtract(mainString, givenValuesString2)); console.log(subtract(mainString, givenValuesString3)); console.log(subtract(mainString, givenValuesString4));

In general, you'd avoid any method that uses O(n²) time complexity (the ones above are not). That's because if the main string is 1,000,000 entries and the "removal" string is 500,000 entries, you'd be look at 1,000,000 x 500,000 = 500,000,000,000 steps (roughly speaking, in that order of magnitude).

Answer 2

You can try this:

var mainString = "1,2,3,4,5";
var givenString ="2,3";

var strarr = mainString.split(",");
var givarr = givenString.split(",");

var output = strarr.filter(function(val){
    return !givarr.includes(val);
});

var desiredOutput = output.join(',');

Answer 3

You can use the following:

 const mainString = "1,2,3,4,5"; const givenValuesString1 = "1"; const givenValuesString2 = "2,3"; const givenValuesString3 = "5"; const givenValuesString4 = "3,5"; const removeFromCsv = (values, filterValues) => values .split(",") .filter(v => !filterValues.split(",").includes(v)) .join(","); console.log( removeFromCsv(mainString, givenValuesString1), // 2,3,4,5 "-", removeFromCsv(mainString, givenValuesString2), // 1,4,5 "-", removeFromCsv(mainString, givenValuesString3), // 1,2,3,4 "-", removeFromCsv(mainString, givenValuesString4) // 1,2,4 );

Answer 4

Use string.split() function to convert your string to array, then iterate to remove the elements, then use array.join() function to convert the resulting array back to string.

 // mainString var mainString = '1,2,3,4,5' // Values to subtracted from mainString var givenValuesString1 = '1' var givenValuesString2 = '2,3' var givenValuesString3 = '5' var givenValuesString4 = '3,5' // Desired Output Values var desiredOutput1 = '2,3,4,5' var desiredOutput2 = '1,4,5' var desiredOutput3 = '1,2,3,4' var desiredOutput4 = '1,2,4' var arr1 = mainString.split(",") console.log("arr1") console.log(arr1) var arrToBeDeleted1 = givenValuesString1.split(",") console.log("arrToBeDeleted1") console.log(arrToBeDeleted1) var arrOutput1 = arr1.slice() // copy the array console.log("arrOutput1") console.log(arrOutput1) for(var i = 0; i < arrToBeDeleted1.length; i++) { var toBeDeleted1 = arrToBeDeleted1[i] var index1 = arr1.indexOf(toBeDeleted1) console.log("index1") console.log(index1) arrOutput1.splice(index1, 1) console.log("arrOutput1") console.log(arrOutput1) } console.log(arrOutput1.join(","))

Answer 5

I have achieved this by using string .split() and by filtering the array.

Here is the code :

 function processStr(data){ var mainStr = "1,2,3,4,5" var arrStr = mainStr.split(',') var filteredArr = arrStr.filter(function(obj) { return data.indexOf(obj) == -1; }); var result = filteredArr.toString(); return result } var str1 = processStr('1,2,3') var str2 = processStr('1') var str3 = processStr('2,3') var str4 = processStr('1,4') console.log(str1) console.log(str2) console.log(str3) console.log(str4)

Let me know if it helps you

Answer 6

in your case you have 2 input parameters :

1. main string like '1,2,3,4,5'
2. blacklist like '2,4'

and you want a string as a result that include main string numbers without numbers in blacklist
see, explain is easier.

so I offer this way :

// first define your variables
let main = '1,2,3,4,5';
let blacklist = '3,4';

// now let's make result
let result = main
            .split(',') // split function make an array from your string with delimiter coma => [1,2,3,4,5]
            .filter( // filter function is a simple loop that decrease array with your condition
                 item => blacklist.indexOf(item)==-1 // if current item is in black list ignore it
            )
            .join (','); // and finaly join array elements with coma to make result as string

console.log(result); //tada , it is what you need => '1,2,5'