Python Functions and Tricks Cheat Sheet

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CheatSheet Python 5 - Functions and 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[0], ['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])))
# [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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