Compare Values within List in Python (Example)

This article illustrates how to compare elements within a list in the Python programming language. To be more precise, the article will consist of the following content blocks:

With that, letâ€™s just jump right in.

Importing Module & Creating Example Data

First, we need to import the itertools module since we will need its functionality in this tutorial.

`import itertools                                      # import itertools`

As a next step, we will create a sample list for demonstration.

```mylist = [1, 2, 3, 4, 2]                              # create sample list

print(mylist)                                         # print mylist
# [1, 2, 3, 4, 2]```

In the next section, we will compare each element pair in `mylist`. Without further ado, letâ€™s jump into the example!

Example: Compare Elements within List

First, we will define a function assessing pairs of elements and returning the output: lower, higher, or equal based on the comparison.

```def compare(a, b):                                    # define comparison function
if a < b:
return "lower"
elif a > b:
return "higher"
else:
return "equal"```

If you are familiar with if-else statements and user-defined functions in Python, the previous step should be a simple piece of code for you. If not, please click on the highlighted terms above.

The next step is to set a for loop to iterate through all possible pairs in `mylist`. To extract all possible pairs in a list, we will employ the combinations function of the itertools module.

This for loop will print an f string returning the elements being compared and the result of the comparison for each element pair. Here you go!

```for a, b in itertools.combinations(mylist, 2):        # iterate through each pair
print(f"Comparing {a} and {b}: {compare(a, b)}")  # print comparison result
# Comparing 1 and 2: lower
# Comparing 1 and 3: lower
# Comparing 1 and 4: lower
# Comparing 1 and 2: lower
# Comparing 2 and 3: lower
# Comparing 2 and 4: lower
# Comparing 2 and 2: equal
# Comparing 3 and 4: lower
# Comparing 3 and 2: higher
# Comparing 4 and 2: higher```

As seen above, we got the comparison for all elements within `mylist`. Well done!

Video & Further Resources

Some time ago I have published a video on my YouTube channel, which shows the contents of this tutorial. Please find the video below:

Besides that, you may read the related posts on my website. I have released several tutorials on similar topics such as indices, data conversion, lists, and groups:

At this point you should know how to evaluate values against each other in the Python programming language. Donâ€™t hesitate to tell me about it in the comments, in case you have any further comments or questions.

This page was created in collaboration with Cansu Kebabci. Have a look at Cansuâ€™s author page to get more information about her professional background, a list of all his tutorials, as well as an overview on her other tasks on Statistics Globe.

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