I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.

I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.

I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.
Dec 3, 2020 in Python 711 views

## 1 answer to this question.

Here's a generator that yields the chunks you want:

```def chunks(lst, n):
"""Yield successive n-sized chunks from lst."""
for i in range(0, len(lst), n):
yield lst[i:i + n]
```

```import pprint
pprint.pprint(list(chunks(range(10, 75), 10)))
[[10, 11, 12, 13, 14, 15, 16, 17, 18, 19],
[20, 21, 22, 23, 24, 25, 26, 27, 28, 29],
[30, 31, 32, 33, 34, 35, 36, 37, 38, 39],
[40, 41, 42, 43, 44, 45, 46, 47, 48, 49],
[50, 51, 52, 53, 54, 55, 56, 57, 58, 59],
[60, 61, 62, 63, 64, 65, 66, 67, 68, 69],
[70, 71, 72, 73, 74]]
```

If you're using Python 2, you should use xrange() instead of range():

```def chunks(lst, n):
"""Yield successive n-sized chunks from lst."""
for i in xrange(0, len(lst), n):
yield lst[i:i + n]
```

Also you can simply use list comprehension instead of writing a function, though it's a good idea to encapsulate operations like this in named functions so that your code is easier to understand. Python 3:

```[lst[i:i + n] for i in range(0, len(lst), n)]
```

Python 2 version:

`[lst[i:i + n] for i in xrange(0, len(lst), n)]`
• 65,910 points

## How to split a string into a list?

You can use the function  text.split() This should be ...READ MORE

## How do I turn a list into numpy array?

Use this line: numpy_array = np.array(list) And printing/displaying the ...READ MORE

## How do you convert two lists into a dictionary?

There are three different ways of converting ...READ MORE

## how do i change string to a list?

suppose you have a string with a ...READ MORE

## how can i randomly select items from a list?

You can also use the random library's ...READ MORE

+1 vote

## how can i count the items in a list?

Syntax :            list. count(value) Code: colors = ['red', 'green', ...READ MORE

## How do you get a list of all the keys in a dictionary?

Hey, @Roshin, I would like to give you ...READ MORE

## How to split a string into a list?

Using For loop This approach uses for loop ...READ MORE