range() in python

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*Memo:

• My post explains a range.
• My post explains enumerate().
• My post explains zip().

range() can create a range in the range [start, stop) as shown below:

*Memo:

• The 1st argument is start or stop(Required-Type:int):
  • It's a start index(inclusive) or stop index(exclusive).
  • Don't use start= or stop=.
• The 2nd argument is stop(Optional-Type:int):
  • It's a stop index(exclusive).
  • Don't use stop=.
• The 3rd argument is step(Optional-Default:1-Type:int):
  • It's the interval of elements.
  • It cannot be 0.
  • Don't use step=.
• Only if one argument is set, the 1st argument is stop, creating the range in the range [0, stop).
• start and stop can be signed indices(zero and positive and negative indices).

v1 = range(5)
v1 = range(0, 5)
v1 = range(0, 5, 1)

print(v1)
# range(0, 5)

print(v1.start, v1.stop, v1.step)
# 0 5 1

print(v1[0], v1[1], v1[2], v1[3], v1[4])
# 0 1 2 3 4

v2 = v1[1:4]

print(v2)
# range(1, 3)

for i in v2:
    print(i)
# 1
# 2
# 3

for i in range(-10, 10, 3):
    print(i)
# -10
# -7
# -4
# -1
# 2
# 5
# 8

for i in range(10, -10, -3):
    print(i)
# 10
# 7
# 4
# 1 
# -2
# -5
# -8

print(list(zip(range(5), range(-10, 10, 3), range(10, -10, -3))))
# [(0, -10, 10), (1, -7, 7), (2, -4, 4), (3, -1, 1), (4, 2, -2)]

print(list(zip(range(5), range(-10, 10, 3), range(10, -10, -3)))[0])
# (0, -10, 10)

i, j, k = list(zip(range(5), range(-10, 10, 3), range(10, -10, -3)))[0]
print(i, j, k)
# 0 -10 10

for i, j, k in zip(range(5), range(-10, 10, 3), range(10, -10, -3)):
    print(i, j, k)
# 0 -10 10
# 1 -7 7
# 2 -4 4
# 3 -1 1
# 4 2 -2

enum = enumerate

print(list(enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8)))
# [(8, (0, -10, 10)), (9, (1, -7, 7)), (10, (2, -4, 4)),
#  (11, (3, -1, 1)), (12, (4, 2, -2))]

print(list(enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8))[0])
# (8, (0, -10, 10))

i, jkl = \
  list(enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8))[0]
print(i, jkl)
# 8 (0, -10, 10)

i, (j, k, l) = \
  list(enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8))[0]
print(i, j, k, l)
# 8 0 -10 10

for i, jkl in enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8):
    print(i, jkl)
# 8 (0, -10, 10)
# 9 (1, -7, 7)
# 10 (2, -4, 4)
# 11 (3, -1, 1)
# 12 (4, 2, -2)

for i, (j, k, l) \
  in enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8):
# for i, [j, k, l] \
#   in enum(zip(range(5), range(-10, 10, 3), range(10, -10, -3)), 8):
    print(i, j, k, l)
# 8 0 -10 10
# 9 1 -7 7
# 10 2 -4 4
# 11 3 -1 1
# 12 4 2 -2