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Loops

range(N)​

print(range(5))
print(list(range(5)))
# 0, 1, 2, 3, 4 (the last number is lower than 1)
Output
range(0, 5)
[0, 1, 2, 3, 4]

For loops​

  • Loops: perform a task over and over
for x in ['A', 'B', 'C']:
    print(x + 'A')

# The list is ['A', 'B', 'C']
# for function will concatenate each of them with:
# 1st: x = 'A'
# 2nd: x = 'B'
# ... -> 'A' + 'A' = 'AA' and so on
Output
AA
BA
CA
for i, x in enumerate(['A', 'B', 'C']):
    print(i, x)

# with enumerate, it's just like [(0, 'A'), (1, 'B'), (2, 'C')] (just e.g)
# 1st: i = 0; x = 'A' -> print(i, x) = 0 A
# ... and so on
Output
0 A
1 B
2 C

While loops​

  • While loops: will only run if a condition is met
x = 5
while x != 2:
    print(x)
    x = x - 1
Output
5
4
3
colors = ['red', 'red', 'blue', 'red', 'green']
new_colors = []
i = 0  # the index starts at 0

while colors[i] == 'red':  # this statement will repeatedly execute the statements
    # until the condition inside the bracket is False
    new_colors.append(colors[i])
    # append from the list 'squares' to the list "news_quares"
    i = i + 1

print(new_colors)
Output
['red', 'red']