'for ... in' Statement with List of Tuples

Q

How to use "for ... in" statements with a list of tuples in Python code?

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A

Usually, "for ... in" statements are used with simple lists. But you can also use a "for ... in" statement with a list of tuples. In this case, you can put multiple looping variables inside the loop item:

for (v1, v2, ... ) in list_of_tuples: 
    statement-block
else : 
    statement-block

For example:

>>> for (v1, v2) in [('gallahad','the pure'), ('robin', 'the brave')]:
...    print(v1+", "+v2)
...
gallahad, the pure
robin, the brave

This form of loops is very useful if you want to loop through a "dict" object:

>>> d = {'gallahad': 'the pure', 'robin': 'the brave'}
>>> for (k,v) in d.items():
...    print(k+": "+v)
...
gallahad: the pure
robin: the brave

And it is also very useful if you want to loop through a "list" object:

>>> l = ['tic', 'tac', 'toe']
>>> for (i,v) in enumerate(l):
...    print(i, v)
...
0 tic
1 tac
2 toe

 

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2018-08-14, 226👍, 0💬