Junior Developer Central JS Practice Exercise - 18

 

Question: 

Write a Javascript program to convert a comma-separated values (CSV) string to a 2D array. A new line indicates a new row in the array. 

for eg. 

Input: 

const oldString = `abc,def,ghi

jkl, mno, pqr

stu, vwx, yza`;

Output: 

0: (3) ["abc", " def", " ghi"]

1: (3) ["jkl", " mno", " pqr"]

2: (3) ["stu", " vwx", " yza"]

Answer: 

function createArr(str) {

  return str.split('\n').map(row => row.split(','));

}

> we declare a variable 'createArr' 

> it has one parameter 'str' 

> to explain this function, we shall use the input example in the question above 'oldString'

> we first split the 'str' with the split () method that will return an array of substrings

> the split ('\n') method will return a new array which will have three items 

> each of these items is a row from the 'oldString' mentioned above

>> so after split ('\n) we get 

>> 0: ["abc, def, ghi"]

>> 1: ["jkl, mno, pqr"]

>> 2: ["stu, vwx, yza"]

> but we need a 2 dimensional array 

> so we need to split each of the values, in the row, into an array itself

>> like this: 

>> 0: ["abc", " def", " ghi"]

>> 1: ["jkl", " mno", " pqr"]

>> 2: ["stu", " vwx", " yza"]

> in order to further split each of the values into an array itself we use the map() method

> the map() method creates a new array with the results of calling a function for every array element

> the map() method calls the provided function once for each element in an array 

> our aim is to further split the row elements we have, into an array itself 

> so we use the map () method and call a function, that will be called on each value of the 'row' 

> so we will use the split () method on each values of the 'row' and split them by the 'comma'

> like this .map(row => row.split(',')

> this will be a one line code and we shall return the same