How can I loop 2D array and modify its values

Question

Given 2D array of photos taken while John doe was on trips so I'm asked to rename pictures and replace actual name with city name where a picture was taken.

const photos = [
['photo.jpg', 'kigali','2013-09-05 14:08:09'],
['demmpa.jpg', 'kigali','2013-09-05 14:08:09'],
['third.jpg', 'kibuye','2013-02-05 12:08:09']
['forthpic.jpg', 'kampala','2013-02-05 12:08:09']
]
   photos.map((photo, index)=>{
    photo.filter((photo, index)=> console.log(photo))
    
  })

Actual output

"photo.jpg"
"kigali"
"2013-09-05 14:08:09"
"demmpa.jpg"
"kigali"
"2013-09-05 14:08:09"

Expected output

kigali01.jpg
kigali02.jpg
Kibuye1.jpg
kampala1.jpg

What have you tried. Please give atleast 2 elements in your expected input so we can help you — Tushar Shahi, Oct 08 '21 at 18:26
why the numbering on kigal are with `0` and the others it's without? — gilamran, Oct 08 '21 at 18:29
the first appearing `city` to begin with `0` then increment the number in the same city — Janvier, Oct 08 '21 at 18:37
Are you sure it shouldn't return either `['kigali01.jpg', 'kigali02.jpg', 'Kibuye01.jpg', 'kampala01.jpg']` or `['kigali1.jpg', 'kigali2.jpg', 'Kibuye1.jpg', 'kampala1.jpg']`? The changing style of the numbers if very odd. But also, where's your own attempt? Have you tried to solve this? What issues did you have? Please see [How do I ask and answer homework questions?](https://meta.stackoverflow.com/q/334822) — Scott Sauyet, Oct 08 '21 at 21:00
`0` has to be appended on the first city only and the similar photo taken in the same city @ScottSauyet — Janvier, Oct 08 '21 at 21:09
I think you really need to give another example or two. Also, please show your own attempts. — Scott Sauyet, Oct 08 '21 at 21:21

BadPiggie · Answer 1 · 2021-10-08T19:25:25.420

You can do it using map. And the occurrence will just keep the number of how many times the name is repeated.

Note: if you need to add leading zeros, Please check it out How to output numbers with leading zeros in JavaScript?

const photos = [
  ['photo.jpg', 'kigali','2013-09-05 14:08:09'],
  ['demmpa.jpg', 'kigali','2013-09-05 14:08:09'],
  ['third.jpg', 'kibuye','2013-02-05 12:08:09'],
  ['forthpic.jpg', 'kampala','2013-02-05 12:08:09']
];

const occurrence = {}

const newArray = photos.map(arr => {

  const ext = arr[0].split('.')[1]; // file extension

  if (occurrence[arr[1]]) { // check whether the name is already there
    occurrence[arr[1]]++;
    return `${arr[1]}${occurrence[arr[1]]}.${ext}`;
  }
  
  occurrence[arr[1]] = 1;
  return `${arr[1]}1.${ext}`;

});


console.log(newArray)

JOo · Answer 2 · 2021-10-08T19:00:03.843

1

let photos = [
['photo.jpg', 'kigali','2013-09-05 14:08:09'],
['demmpa.jpg', 'kigali','2013-09-05 14:08:09'],
['third.jpg', 'kibuye','2013-02-05 12:08:09'],
['forthpic.jpg', 'kampala','2013-02-05 12:08:09']
]

 photos = Array.from(photos).map((photo)=>{
 const format = photo[0].split('.')[1]
 photo[0]=photo[1]+'.'+format
 return photo
})

edited Oct 08 '21 at 19:00

answered Oct 08 '21 at 18:47

JOo

17
5

Can you please explain your code? How does it produce the expected output? – BadPiggie Oct 08 '21 at 18:49
first i did a mapping on the photos array next i took the format from the index one then i altred the first index to the city name + the format – JOo Oct 08 '21 at 19:01
The replicated name should have numbers. I think that missing in your code. – BadPiggie Oct 08 '21 at 19:24

How can I loop 2D array and modify its values

2 Answers2