Use the built-in function enumerate():

for idx, x in enumerate(xs):
    print(idx, x)

It is non-Pythonic to manually index via for i in range(len(xs)): x = xs[i] or manually manage an additional state variable.

Check out PEP 279 for more.

Answer from Mike Hordecki on Stack Overflow
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W3Schools
w3schools.com › python › python_lists_loop.asp
Python - Loop Lists
Print all items, using a while loop to go through all the index numbers · thislist = ["apple", "banana", "cherry"] i = 0 while i < len(thislist): print(thislist[i]) i = i + 1 Try it Yourself » · Learn more about while loops in our Python While Loops Chapter.
Top answer
1 of 16
9260

Use the built-in function enumerate():

for idx, x in enumerate(xs):
    print(idx, x)

It is non-Pythonic to manually index via for i in range(len(xs)): x = xs[i] or manually manage an additional state variable.

Check out PEP 279 for more.

2 of 16
1370

Using a for loop, how do I access the loop index, from 1 to 5 in this case?

Use enumerate to get the index with the element as you iterate:

for index, item in enumerate(items):
    print(index, item)

And note that Python's indexes start at zero, so you would get 0 to 4 with the above. If you want the count, 1 to 5, do this:

count = 0 # in case items is empty and you need it after the loop
for count, item in enumerate(items, start=1):
    print(count, item)

Unidiomatic control flow

What you are asking for is the Pythonic equivalent of the following, which is the algorithm most programmers of lower-level languages would use:

index = 0            # Python's indexing starts at zero
for item in items:   # Python's for loops are a "for each" loop 
    print(index, item)
    index += 1

Or in languages that do not have a for-each loop:

index = 0
while index < len(items):
    print(index, items[index])
    index += 1

or sometimes more commonly (but unidiomatically) found in Python:

for index in range(len(items)):
    print(index, items[index])

Use the Enumerate Function

Python's enumerate function reduces the visual clutter by hiding the accounting for the indexes, and encapsulating the iterable into another iterable (an enumerate object) that yields a two-item tuple of the index and the item that the original iterable would provide. That looks like this:

for index, item in enumerate(items, start=0):   # default is zero
    print(index, item)

This code sample is fairly well the canonical example of the difference between code that is idiomatic of Python and code that is not. Idiomatic code is sophisticated (but not complicated) Python, written in the way that it was intended to be used. Idiomatic code is expected by the designers of the language, which means that usually this code is not just more readable, but also more efficient.

Getting a count

Even if you don't need indexes as you go, but you need a count of the iterations (sometimes desirable) you can start with 1 and the final number will be your count.

count = 0 # in case items is empty
for count, item in enumerate(items, start=1):   # default is zero
    print(item)

print('there were {0} items printed'.format(count))

The count seems to be more what you intend to ask for (as opposed to index) when you said you wanted from 1 to 5.


Breaking it down - a step by step explanation

To break these examples down, say we have a list of items that we want to iterate over with an index:

items = ['a', 'b', 'c', 'd', 'e']

Now we pass this iterable to enumerate, creating an enumerate object:

enumerate_object = enumerate(items) # the enumerate object

We can pull the first item out of this iterable that we would get in a loop with the next function:

iteration = next(enumerate_object) # first iteration from enumerate
print(iteration)

And we see we get a tuple of 0, the first index, and 'a', the first item:

(0, 'a')

we can use what is referred to as "sequence unpacking" to extract the elements from this two-tuple:

index, item = iteration
#   0,  'a' = (0, 'a') # essentially this.

and when we inspect index, we find it refers to the first index, 0, and item refers to the first item, 'a'.

>>> print(index)
0
>>> print(item)
a

Conclusion

  • Python indexes start at zero
  • To get these indexes from an iterable as you iterate over it, use the enumerate function
  • Using enumerate in the idiomatic way (along with tuple unpacking) creates code that is more readable and maintainable:

So do this:

for index, item in enumerate(items, start=0):   # Python indexes start at zero
    print(index, item)
Discussions

Why iterate over an array using the index?
You do it if there is something in your loop that will use an index rather than the elements of the array. For instance, sometimes you want to sample something from another array that is not your loop array A cleaner way to do it is by using enumerate function for i, item in enumerate(array): The index gets assigned to i and whatever element of the array gets assigned to item. This may also be a bad habit from Matlab, people that come from Matlab are more used to looping over indexes. More on reddit.com
🌐 r/learnpython
57
46
September 28, 2022
When using for loops are we iterating through the index or the actual values?
A "pure" for loop requires an index because you're just executing the same piece of code for whatever the range of that index is. What you're probably looking for is a foreach loop, which is really just syntactic sugar over a for loop that allows you to specify iterating over every member of a collection without defining an index. In Python it's a little different than a lot of other languages as there's no explicit foreach keyword. You just define your loop like: for season in seasons: More on reddit.com
🌐 r/learnprogramming
14
0
March 8, 2023
Move the starting index of a for loop during the loop if a condition is met
It's not possible to overwrite the iterated item in a for loop. Maybe you want a while loop instead. Most likely you want something else entirely. It is not clear what you're trying to actually accomplish. More on reddit.com
🌐 r/learnpython
11
4
April 29, 2022
In a for in loop, i want to jump my index when 'x' happens. How can I do that?
For loops in python are more like forEach loops in most languages. You can use a while loop to archive what you want. Like java equivalent of python for loop would be: int[] nums = { 1, 2, 3, 4, 5 }; for (int num : nums) { System.out.println(num); num = 300; } } Which will run 5 times, no matter how hard you try to increment num. The i in your example isn't an index or anything, but a value from the list. More on reddit.com
🌐 r/learnprogramming
24
12
September 15, 2022
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Trey Hunner
treyhunner.com › 2016 › 04 › how-to-loop-with-indexes-in-python
How to loop with indexes in Python
This first creates a range corresponding to the indexes in our list (0 to len(colors) - 1). We can loop over this range using Python’s for-in loop (really a foreach). This provides us with the index of each item in our colors list, which is the same way that C-style for loops work.
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GeeksforGeeks
geeksforgeeks.org › python › how-to-access-index-in-for-loop-python
How to Access Index using for Loop - Python - GeeksforGeeks
July 23, 2025 - data = ["java", "python", "HTML", "PHP"] print("Indices:", [i for i in range(len(data))]) print("Elements:", [data[i] for i in range(len(data))]) ... Explanation: [i for i in range(len(data))] creates a list of indices.
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StrataScratch
stratascratch.com › blog › mastering-loop-iterations-python-for-loop-index-explained
Mastering Loop Iterations: Python For Loop Index Explained - StrataScratch
October 17, 2024 - We iterate through the orders_data and modify rows based on the index if the order was canceled by the client. A new column, client_cancelled, is added and set to 1 for these orders. If you want to see more check these Python Interview Questions. When dealing with massive datasets, performance becomes crucial. While for loops with indexes give you control, they're not always the most efficient with big data.
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Sentry
sentry.io › sentry answers › python › accessing the index in a `for` loop in python
Accessing the Index in a `for` Loop in Python | Sentry
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. The enumerate function returns an iterable.
Find elsewhere
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Reddit
reddit.com › r/learnprogramming › when using for loops are we iterating through the index or the actual values?
r/learnprogramming on Reddit: When using for loops are we iterating through the index or the actual values?
March 8, 2023 -
for i in range(10,20):
    print(i)

I understand that i is going through the values 10 to 20. I know there can be an index attached but why do we have to explicitly associate an index to a value to change the value we want?

seasons = ['fall','winter','spring','summer'] # works like the enurate function
    for i in range(len(seasons)):
        if seasons[i] == 'summer':
            seasons[i] = 'New season'
        print(i , seasons[i])

Why do we have to associate the index to change the actual value? What exactly are we looping through

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Python Morsels
pythonmorsels.com › looping-with-indexes
Looping with indexes - Python Morsels
October 8, 2020 - If you think you need to loop with indices, first, ask yourself a question: do I even need some kind of counter as I'm looping? If you don't need a counter, just use a for loop without any frills. But if you do need to count upward while looping, you can use Python's built-in enumerate function to help you do that counting.
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Programiz
programiz.com › python-programming › examples › index-for-loop
Python Program to Access Index of a List Using for Loop
Print the required variables inside the for loop block. The function of enumerate() is to add a counter (i.e. index) to the iterate and return it. my_list = [21, 44, 35, 11] for index, val in enumerate(my_list, start=1): print(index, val) ... The value of the parameter start provides the starting ...
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GeeksforGeeks
geeksforgeeks.org › python › access-the-index-and-value-using-python-for-loop
Access the Index and Value using Python 'For' Loop - GeeksforGeeks
July 23, 2025 - We can also use count from itertools along with zip() to achieve a similar effect. In this example, we have used itertools to access the index value in a for loop.
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Spark By {Examples}
sparkbyexamples.com › home › python › python – access index in for loop with examples
Python - Access Index in For Loop With Examples - Spark By {Examples}
May 31, 2024 - This counter variable is used as an index to access items from sequence type within a for loop. But Python for loop simplified this not to use a counter/index variable and provides a way to loop through each element in an iterable object.
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iO Flood
ioflood.com › blog › python-for-loop-with-index
Learn Python: For Loops With Index (With Examples)
June 7, 2024 - When you’re using a for loop with an index in Python, you’re essentially combining these two concepts: you’re iterating over a sequence with a for loop, and you’re keeping track of the index of each item. This can be incredibly useful in many scenarios, as we’ve seen in the previous sections.
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Real Python
realpython.com › python-enumerate
Python enumerate(): Simplify Loops That Need Counters – Real Python
June 23, 2025 - Python’s enumerate() function helps you with loops that require a counter by adding an index to each item in an iterable. This is particularly useful when you need both the index and value while iterating, such as listing items with their ...
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Vultr
docs.vultr.com › python › examples › access-index-of-a-list-using-for-loop
Python Program to Access Index of a List Using for Loop | Vultr Docs
November 25, 2024 - You'll explore the use of enumerate(), loop iteration with the range() function, and how to implement these in practical examples. Utilize enumerate() to get both the index and value of items in a list.
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Python Guides
pythonguides.com › python-for-loop-index
How to Use Python For Loop with Index
October 14, 2025 - Modifying the list while looping: Avoid changing the list (adding or removing elements) inside the for loop. It can cause unexpected behavior or index errors. Using wrong start index: Remember that Python uses zero-based indexing. If you want a human-readable index, start from 1 using enumerate(states, start=1). Forgetting tuple unpacking: When using enumerate(), make sure to unpack both the index and the item correctly: ... Let’s say you have a list of states and their populations, and you want to print them in a formatted way with their index.
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PythonHow
pythonhow.com › how › accesses-the-index-in-for-loops
Here is how to accesses the index in for loops in Python
September 24, 2024 - colors = ['red', 'green', 'blue'] # Loop over the elements in the list and print their index and value for i, color in enumerate(colors): print(f'{i}: {color}')
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Educative
educative.io › answers › how-to-loop-through-a-list-using-the-index-numbers-in-python
How to loop through a list using the index numbers in Python
The combination of the range() and len() functions, (range(len(iterable), is used to iterate over a list in Python. Using the two functions together, we can refer to the index numbers of all items or elements in a list.
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Codingem
codingem.com › home › python for loop with index: access the index in a for loop
Python For Loop with Index: Access the Index in a For Loop - codingem.com
March 14, 2024 - To access the for loop index in Python, use the enumerate() function. It couples each element with an index.
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Stack Abuse
stackabuse.com › how-to-access-index-in-pythons-for-loop
How to Access Index in Python's for Loop
August 1, 2025 - We iterate from 0..len(my_list) with the index. Then, we use this index variable to access the elements of the list in order of 0..n, where n is the end of the list. ... enumerate() is a built-in Python function which is very useful when we want to access both the values and the indices of a list.