What is the difference between these two lines of codes

Python
1

I was making a simple project with python.

Here is the code:

from random import choice
countries = ["sweden","norway,"hungary","italy","germany","austria"]
for x in range(6):
          print(choice(countries))


from random import choice
countries = ["sweden","norway,"hungary","italy","germany","austria"]
for x in countries:
  print(choice(choice))

Both are giving me the same kind of result

First output


italy
germany
germany
hungary
sweden
sweden

Second output

germany
norway
hungary
sweden
hungary
norway

The result are different in both the cases but they are giving me same kind of result.

Threfore I would to know what is the reason behind it and how these two pieces of codes are different.

THANK YOU

2
  1. What does choice do?
  2. for x in range(6): x = 0, 1,… 5
  3. print(choice(countries)) does (whatever choice does) with countries as its argument 6 times
  4. for x in countries: x = “sweden”,"norway,…,“austria”
  5. print(choice(choice)) does (whatever choice does) with choice itself as its argument 6 Times

Edit: I see choice is a standard random # generator lib https://pynative.com/python-random-choice/

So given a sequence (ex. the list of countries) , choice(countries) outputs a randomly selected country from the list, in the first one you are repeating that random selection 6 times, in the second one choice(choice) is not given a sequence as an argument and should technically error out.

Edit: Unless of course you made a typo and meant choice(countries) for the second one as well, in that event it is pretty much identical as the first one since as I explained above the second loop is iterating through the list of countries (which has a length of 6) while the first loop is iterating through a fixed number of the same length.

3

As @Dereje1 pointed out, the biggest difference (other than what I think is a typo) is what x is equal to in each iteration of the for loop. Since this particular loop doesn’t need to reference x, there isn’t a functional difference in the end. Your loop only needs to do something six times, both loop setups accomplish this. But in a lot of loop instances the item or the item’s index in the list needs to be known.

Consider these:

example = ['a', 'b', 'c', 'd', 'e', 'f', 'g']

# If you only need to access each item of example individually:
for x in example:
    print(x)
# a
# b
# c
# d
# e
# f
# g

# But what if we need to access or compare other items of the list in each loop iteration?
# Knowing the list index at each iteration makes this possible
for i in range(len(example)):  # len(example) == 7 --> range(7) --> [0, 1, 2, 3, 4, 5, 6]
    if i > 0:
        print(f"Item i: {example[i]}, Item i-1: {example[i-1]}, Current Index: {i}")
# Item i: b, Item i-1: a, Current Index: 1
# Item i: c, Item i-1: b, Current Index: 2
# Item i: d, Item i-1: c, Current Index: 3
# Item i: e, Item i-1: d, Current Index: 4
# Item i: f, Item i-1: e, Current Index: 5
# Item i: g, Item i-1: f, Current Index: 6

#Python also offers the enumerate() function for such cases
for i, x in enumerate(example):
    print(f"Index: {i}, Item: {x}")
# Index: 0, Item: a
# Index: 1, Item: b
# Index: 2, Item: c
# Index: 3, Item: d
# Index: 4, Item: e
# Index: 5, Item: f
# Index: 6, Item: g

# All of these can be used as list comprehensions as well.
test = [(f"i: {i}", f"x: {x}") for i,x in enumerate(example)]
print(f"Array of results: {test}")
# Array of results: [('i: 0', 'x: a'), ('i: 1', 'x: b'), ('i: 2', 'x: c'), ('i: 3', 'x: d'), ('i: 4', 'x: e'), ('i: 5', 'x: f'), ('i: 6', 'x: g')]
4