how to zip function with two arrays as a return value - Python

Question

how do I create tuple from two randomly generated lists with separate function ? zip function will create only tuple of those two arrays as whole but I need the numbers to be coupled like (1,2),(3,4). Thanks.

import random
def ars():
    arr1 = []
    arr2 = []
    for i in range(10):
        x = random.randrange(100)
        arr1.append(x)
    for j in range(10):
        y = random.randrange(100)
        arr2.append(y)
    return(arr1,arr2)

x = ars()
print x
y = zip(ars())
print y

vaultah · Accepted Answer · 2014-05-15T12:11:31.137

2

zip function accepts multiple iterables as its arguments, so you simply have to unpack the values from the returned tuple with * (splat operator):

y = zip(*ars())

With zip(([1], [2])) only one iterable is submitted (that tuple).

In zip(*([1], [2])) you unpack 2 lists from tuple, so zip receives 2 iterables.

edited May 15 '14 at 12:11

answered May 15 '14 at 12:00

vaultah

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Ah, you turned green, I see. – thefourtheye May 15 '14 at 12:03
* is the "splat" operator: It takes a list as input, and expands it into actual positional arguments in the function call. Found http://stackoverflow.com/questions/5239856/foggy-on-asterisk-in-python – SkyDive May 15 '14 at 12:05
@thefourtheye, you liked the old avatar? :) – vaultah May 15 '14 at 12:17
@SkyDive you can also do `**some_dict` to unpack key->value pairs from `some_dict` to the keyword arguments. – vaultah May 15 '14 at 12:19
Who doesn't like the GO Green avatar ;-) – thefourtheye May 15 '14 at 12:21

score 2 · Answer 2 · answered May 15 '14 at 12:24

You can avoid having to zip by using map

def ars(arr_len, rand_max):
    return [map(random.randrange, [rand_max]*2) for x in range(arr_len)]

call ars like: ars(10,100), if you really need tuples instead of lists, wrap the map statement in a tuple() function.

how to zip function with two arrays as a return value - Python

2 Answers2