Python cheat sheets are the 80/20 principle applied to coding: learn 80% of the language features in 20% of the time.
Download and pin this cheat sheet to your wall until you feel confident using all these tricks.
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Try It Yourself:
Exercise: Modify each function and play with the output!
Here’s the code for copy&paste:
# 1. map(func, iter) m = map(lambda x: x, ['red', 'green', 'blue']) print(list(m)) # ['r', 'g', 'b'] # 2. map(func, i1, ...,ik) l1 = [0, 2, 2] l2 = ['apple', 'orange', 'banana'] m = map(lambda x, y: str(x) + ' ' + str(y) + 's', l1, l2) print(list(m)) # ['0 apples', '2 oranges', '2 bananas'] # 3. string.join(iter) print(' marries '.join(['Alice', 'Bob'])) # Alice marries Bob # 4. filter(func, iterable) print(list(filter(lambda x: x>17, [1, 15, 17, 18]))) #  # 5. string.strip() print(" \n \t 42 \t ".strip()) # 42 # 6. sorted(iter) print(sorted([8, 3, 2, 42, 5])) # [2, 3, 5, 8, 42] # 7. sorted(iter, key=key) print(sorted([8, 3, 2, 42, 5], key=lambda x: 0 if x==42 else x)) # [42, 2, 3, 5, 8] # 8. help(func) help(str.upper) ''' Help on method_descriptor: upper(self, /) Return a copy of the string converted to uppercase. ''' # 9. zip(i1, i2, ...) print(list(zip(['Alice', 'Anna'], ['Bob', 'Jon', 'Frank']))) # [('Alice', 'Bob'), ('Anna', 'Jon')] # 10. Unzip print(list(zip(*[('Alice', 'Bob'), ('Anna', 'Jon')]))) # [('Alice', 'Anna'), ('Bob', 'Jon')] # 11. Enumerate print(list(enumerate(['Alice', 'Bob', 'Jon']))) # [(0, 'Alice'), (1, 'Bob'), (2, 'Jon')]
The following tutorials address those functions in great detail (including videos on the most important functions).
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