For Example, if I had two lists:
listA = [1, 2, 3, 4, 5]
listB = [red, blue, orange, black, grey]
I'm trying to figure out how to display the elements in the two argument lists in two columns,
assigning 1: red, 2: blue... and so on.
This has to be done without using the built-in zipfunction.
>>> listA = [1, 2, 3, 4, 5]
>>> listB = ["red", "blue", "orange", "black", "grey"]
>>> dict(zip(listA, listB))
{1: 'red', 2: 'blue', 3: 'orange', 4: 'black', 5: 'grey'}
dict? The order that the dict prints is not guaranteed.
zip approach is slower than doing this task in a simple for loop. In my tests, the for loop approach came up twice as fast as the zip approach, although the zip approach reads more elegantly.If you can't use zip, do a for loop.
d = {} #Dictionary
listA = [1, 2, 3, 4, 5]
listB = ["red", "blue", "orange", "black", "grey"]
for index in range(min(len(listA),len(listB))):
# for index number in the length of smallest list
d[listA[index]] = listB[index]
# add the value of listA at that place to the dictionary with value of listB
print (d) #Not sure of your Python version, so I've put d in parentheses
Special Teacher edition:
list_a = [1, 2, 3, 4, 5]
list_b = ["red", "blue", "orange", "black", "grey"]
for i in range(min(len(list_a), len(list_b))):
print list_a[i], list_b[i]
I suspect your teacher wants you to write something like
for i in range(len(listA)):
print listA[i], listB[i]
However this is an abomination in Python.
Here is one way without using zip
>>> listA = [1, 2, 3, 4, 5]
>>> listB = ["red", "blue", "orange", "black", "grey"]
>>>
>>> b_iter = iter(listB)
>>>
>>> for item in listA:
... print item, next(b_iter)
...
1 red
2 blue
3 orange
4 black
5 grey
However zip is the natural way to solve this, and your teacher should be teaching you to think that way
Usually, zip is the best way to solve your problem. But as it is a homework, and your teacher does not allow you to use zip, I think you can take any solution from this page.
And I provide a version of using a lambda function. Note that if the length of both lists are not identical, a None will be printed at the corresponding place.
>>> list_a = [1, 2, 3, 4, 5]
>>> list_b = ["red", "blue", "orange", "black", "grey"]
>>> for a,b in map(lambda a,b : (a,b), list_a, list_b):
... print a,b
...
1 red
2 blue
3 orange
4 black
5 grey
dict? Why are you and the other two answers usingdicthere?1: red, 2:bluemislead me to creating a dict. Also he wants the problem being solved without usingzip. It seems to be kind of a homework question...