Python tips

How to put all lines of a file into an array in Python ?

You can read a multiline file in different ways. Some of them are less verbose than the others and in this tip I will focus on one-line solution materializing the who le input at once. But let's begi...

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How to use defaultdict in nested array in Python?

defaultdict helps to reduce boilerplate code in Python. Using it in normal circumstances is very easy: from collections import defaultdict default_int_dict = defaultdict(int) default_int_dict...

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How to merge 2 dictionaries in Python?

There are multiple ways to achieve that but my favorite is the following: dict_1 = {'a': 10, 'b': 20, 'c': 30} dict_2 = {'c': 40, 'd': 50, 'e': 60} merged_dict = {dict_key: dict_1.get(dict_key,...

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How to get a random element from an array in Python?

For a long time to access a random element in an array I used something like: import random letters = ['a', 'b', 'c', 'd'] random_letter = letters[random.randint(0, len(letters)-1)] assert r...

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How to convert a dictionary into a list of tuples?

The goal is to transform a dictionary into a list of tuples where the key will be the first part of the tuple and the value the second part. To do this in Python we can use comprehensions: data = {...

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How to create a time-aware Python cache without extra dependencies?

One of native methods supporting caching in Python is @lru_cache decorator. It caches method execution by parameters and it's the key of the solution proposed in this tip. Since the cache is parame...

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How to unpack the middle of a collection in Python 3.5?

Let's suppose that we have a list like input_list = [1, 2, 3, 4, 5, 6] and we want to retrieve from it 3 variables, a=1, b=[2, 3, 4, 5] and c=6. A primitive solution to that problem could be: a, b,...

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How to get first or last X values from a Python collection?

Python has an interesting method called slice. This function generates a slice which is a set of indices between start and stop every step elements. s: letters = ["a", "b", "c", "d", "e", "f", "g"]...

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How to convert a defaultdict to dict in Python?

If for whatever reason you need a function returning a dictionary from a defaultdict, you can simply convert it that way: from collections import defaultdict default_int_dict = defaultdict(int) ...

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