Iterating through two arrays at the same time

Question

In Python, I can zip two arrays together and iterate through them at the same time (without using indices). E.g.
```python
list1 = [1, 2, 3, 4]
list2 = [9, 8, 7, 6]
for a, b in zip(list1, list2):
    print(a + b)
``
will return10` for four times.
Is this possible in JS?
Also, there is something called enumerate(...) in Python, which takes an iterable as the input, and returns a list of indices and a list of the elements. E.g.
```python
my_list = ["apple", "orange", "banana"]
for index, value in enumerate(my_list):
    print(index, value)
```
This will return the fruit names with their indices on the left.
What would be the equivalent way to do this in JS?

Steven Parker · Accepted Answer

Here's some JavaScript ways to approximate the same tasks (Python code in comments):
```js
// for a, b in zip(list1, list2):
//     print(a + b)
list1.forEach((a, i) => console.log(a + list2[i]));
// for index, value in enumerate(mylist):
//     print(index, value)
mylist.map((value, index) => console.log(index, value));

And if we define "zip" first, we can make an equivalent to that first one that looks very much like the Python:
js
var zip = (a,b) => a.map((x,i) => [x,b[i]]);
// for a, b in zip(list1, list2):
for (let [a, b] of zip(list1, list2))
//     print(a + b)
     console.log(a + b);
```

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Kip Yin

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Iterating through two arrays at the same time

1 Answer

Steven Parker

Steven Parker

Kip Yin

Kip Yin

Steven Parker

Steven Parker

Kip Yin

Kip Yin