Iterate Over Dictionary

Question

The two setups using print(i, j) and print(i) return the same result. Are there cases when one should be used over the other or is it correct to use them interchangeably?

desc = {'city': 'Monowi', 'state': 'Nebraska', 'county':'Boyd', 'pop': 1}

for i, j in desc.items():
 print(i, j)

for i in desc.items():
 print(i)

for i, j in desc.items():
 print(i, j)[1]

for i in desc.items():
 print(i)[1]

Possible duplicate of [Iterating over dictionaries using 'for' loops](https://stackoverflow.com/questions/3294889/iterating-over-dictionaries-using-for-loops) — oshaiken, Feb 02 '18 at 15:14
They're functionally equivalent, so use whichever makes your code more readable. — Aran-Fey, Feb 02 '18 at 15:18
In Python 3, they are _not_ equivalent: The first prints the items seperated by a space, the second prints a tuple. — L3viathan, Feb 02 '18 at 15:20
If you need to use the keys and values separately then use the first approach, this is the most common case for iterating over a `dict` — Chris_Rands, Feb 02 '18 at 15:21

score 12 · Accepted Answer · answered Feb 02 '18 at 15:24

Both are different if remove parenthesis in print because you are using python 2X

desc = {'city': 'Monowi', 'state': 'Nebraska', 'county':'Boyd', 'pop': 1}

for i, j in desc.items():
 print i, j 

for i in desc.items():
 print i

output

county Boyd
city Monowi
state Nebraska
pop 1
('county', 'Boyd')
('city', 'Monowi')
('state', 'Nebraska')
('pop', 1)

score 1 · Answer 2 · edited Oct 05 '21 at 18:23

1

In Python 3, print(i, j) and print(i) does not return the same result.

print(i, j) prints the key i followed by its value j.

print(i) prints a tuple containing the dictionary key followed by its value.

edited Oct 05 '21 at 18:23

Owen

7,494
10
42
52

answered Feb 02 '18 at 15:22

A.B.

169
10

score 0 · Answer 3 · answered Feb 02 '18 at 15:23

items() returns a view object which allows you to iterate over the (key, value) tuples. So basically you can just manipulate them as what you do with tuples. The document may help:

iter(dictview) Return an iterator over the keys, values or items (represented as tuples > of (key, value)) in the dictionary.

Also I think print(i, j)[1] would result in error in Python 3 since print(i, j) returns None.

Iterate Over Dictionary

3 Answers3