# Python: Access the Index in a for Loop

> Get the index of each item in a Python for loop using the built-in enumerate function, including how to change its starting index value

**URL:** https://sentry.io/answers/accessing-the-index-in-a-for-loop-in-python/

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## The Problem

How can you access the index of each element while using Python's `for` loop?

Let's say we have the following list:

```python
directions = ['north', 'east', 'south', 'west']
```

Usually, we don't need the indexes of the elements. So Python provides a simpler method of looping where instead of retrieving item indexes and looking up each element, we can just loop over the elements directly, like so:

```python
directions = ['north', 'east', 'south', 'west']

for direction in directions:
	print(direction)
```

But what if we need the indexes? For example, if we want the following output where each element is printed alongside its index in the list:

```
0 north
1 east
2 south
3 west
```

## The Solution

Python's `for` loops are actually [foreach loops](https://en.wikipedia.org/wiki/Foreach_loop). A foreach loop makes the code simpler to read but it maintains no counters. So rather than saying "do this _n_ times", a foreach loop essentially says "do this to everything in the sequence".

For scenarios where we actually need the index or counter variable, we can use Python's built-in [`enumerate` function](https://docs.python.org/3/library/functions.html#enumerate). The `enumerate` function returns an [iterable](https://docs.python.org/3/glossary.html#term-iterable). Each element of this iterable is a tuple containing the index of the item and the original item value, like so:

```python
directions = ['north', 'east', 'south', 'west']
directions_tuples = enumerate(directions)

# output [(0, 'north'), (1, 'east'), (2, 'south'), (3, 'west')]
```

We can unpack the tuple in two variables and use it in the `for` loop, like so:

```python
directions = ['north', 'east', 'south', 'west']

for index, direction in enumerate(directions):
	print(f"{index} {direction}")
```

This will print the following output:

```
0 north
1 east
2 south
3 west
```

The `enumerate` function also takes an optional argument, `start`. We can use this argument to change the starting index. By default, the value of `start` is 0.

Let's say we want to print the directions with a natural counting number, we can set the value of `start` to 1, like so:

```python
directions = ['north', 'east', 'south', 'west']

for index, direction in enumerate(directions, start=1):
	print(f"{index} {direction}")
```

This time we will get the following output:

```
1 north
2 east
3 south
4 west
```

There are other ways of accessing index or counter variables, for example using the `range` and `len` functions, like so:

```python
for index in range(len(directions)):
	print(f"{index} {directions[index]}")
```

But using the `enumerate` function is the recommended and [pythonic](https://docs.python-guide.org/writing/style/) way of achieving this result.

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*Source: [sentry.io/answers/accessing-the-index-in-a-for-loop-in-python/](https://sentry.io/answers/accessing-the-index-in-a-for-loop-in-python/)*