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Technical articles with clear explanations and examples

Remove all occurrences of a multiple occurring element in an array in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 871 Views

We are required to write a JavaScript function that takes in an array of literal values.The array might contain some repeating values.Our function should remove all the values from the array that are repeating. We are required to remove all instances of all such elements.ExampleThe code for this will be −const arr = [1, 2, 3, 2, 4]; const removeAllInstances = (arr = []) => {    filtered = arr.filter(val => {       const lastIndex = arr.lastIndexOf(val);       const firstIndex = arr.indexOf(val);       return lastIndex === firstIndex;    });    return filtered; }; console.log(removeAllInstances(arr));OutputAnd the output in the console will be −[ 1, 3, 4 ]

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Combine array of objects in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 395 Views

Suppose, we have an array of objects that contains data about some students like this −const arr = [{    name: 'A',    idNo: 1,    marks: {       math: 98,       sci: 97,       eng: 89    } }, {    name: 'B',    idNo: 2,    marks: {       math: 88,       sci: 87,       eng: 79    } }, {    name: 'C',    idNo: 3,    marks: {       math: 87,       sci: 98,       eng: 91   ...

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How to add a straight line to a plot in R starting from bottom left and ending at top right?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 23-Nov-2020 204 Views

The abline function can give us a straight line from intercept 0 with slope 1 in an existing plot. We would need to pass the coefficients inside the function as abline(coef = c(0,1)). Therefore, we can use this function to add a line starting from bottom left and ending at top right. This is also called diagonal line because it joins the end points on one side with the opposite of the other side.Example> plot(1:10,type="n") > abline(coef=c(0,1))Output:

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Filter JavaScript array of objects with another array

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 622 Views

Suppose, we have an array of objects like this −const arr = [    {area: 'NY', name: 'Bla', ads: true},    {area: 'DF', name: 'SFS', ads: false},    {area: 'TT', name: 'SDSD', ads: true},    {area: 'SD', name: 'Engine', ads: false},    {area: 'NSK', name: 'Toyota', ads: false}, ];We are required to write a JavaScript function that takes in one such array as the first argument and an array of string literals as the second argument.Our function should then filter the input array of objects to contain only those objects whose "area" property is included in the array of literals ...

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Remove the duplicate value from array with images data in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 486 Views

Suppose, we have some data regarding some images in an array like this −const arr = [{    'image': "jv2bcutaxrms4i_img.png",    'gallery_image': true }, {    'image': "abs.png",    'gallery_image': true }, {    'image': "acd.png",    'gallery_image': false }, {    'image': "jv2bcutaxrms4i_img.png",    'gallery_image': true }, {    'image': "abs.png",    'gallery_image': true }, {    'image': "acd.png",    'gallery_image': false }];We are required to write a JavaScript function that takes in one such array.Our function should remove the objects from the array that have duplicate values for the 'image' property.ExampleThe code for this will be −const arr ...

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How to display central limit theorem using uniform random variable in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 23-Nov-2020 225 Views

The central limit theorem says that as the sample size increases the distribution of the sample means approaches normal distribution. Therefore, irrespective of the actual population distribution if we take samples of larger size and find the mean of these samples then the distribution of these sample means will be approximately normal. We can display this in R, by creating the histogram of such type of means.Example1> x y

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Grouping nested array in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 847 Views

Suppose, we have an array of values like this −const arr = [    {       value1:[1, 2],       value2:[{type:'A'}, {type:'B'}]    },    {       value1:[3, 5],       value2:[{type:'B'}, {type:'B'}]    } ];We are required to write a JavaScript function that takes in one such array. Our function should then prepare an array where the data is grouped according to the "type" property of the objects.Therefore, for the above array, the output should look like −const output = [    {type:'A', value: [1, 2]},    {type:'B', value: [3, 5]} ];ExampleThe code ...

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JavaScript: create an array of JSON objects from linking two arrays

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 527 Views

Suppose, we have two arrays like these −const meals = ["breakfast", "lunch", "dinner"]; const ingredients = [    ["eggs", "yogurt", "toast"],    ["falafel", "mushrooms", "fries"],    ["pasta", "cheese"] ];We are required to write a JavaScript function that takes in two such arrays and maps the subarrays in the second array to the corresponding strings of the first array.Therefore, the output for the above arrays should look like −const output = {    "breakfast" : ["eggs", "yogurt", "toast"],    "lunch": ["falafel", "mushrooms", "fries"],    "dinner": ["pasta", "cheese"] };ExampleThe code for this will be −const meals = ["breakfast", "lunch", "dinner"]; const ingredients ...

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Combining two arrays in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 276 Views

We are required to write a JavaScript function that takes in two arrays of the same length.Our function should then combine corresponding elements of the arrays, to form the corresponding subarray of the output array, and then finally return the output array.If the two arrays are −const arr1 = ['a', 'b', 'c']; const arr2 = [1, 2, 3];Then the output should be −const output = [    ['a', 1],    ['b', 2],    ['c', 3] ];ExampleThe code for this will be −const arr1 = ['a', 'b', 'c']; const arr2 = [1, 2, 3]; const combineCorresponding = (arr1 = [], arr2 ...

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Remove item from a nested array by indices in JavaScript

AmitDiwan
AmitDiwan
Updated on 23-Nov-2020 1K+ Views

Suppose, we have a nested array of objects like this −const arr = [    { value: 'some value' },    {       array: [          { value: 'some value' },          {             array: [                { value: 'some value' },                { value: 'some value' },             ],          },          { value: 'some value' },          {   ...

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