How to create tuple with a loop in python

问题

I want to create this tuple:

a=(1,1,1),(2,2,2),(3,3,3),(4,4,4),(5,5,5),(6,6,6),(7,7,7),(8,8,8),(9,9,9)

I tried with this

a=1,1,1
for i in range (2,10):
    a=a,(i,i,i)

However it creates a tuple inside other tuple in each iteration.

Thank you

回答1:

Use an extra comma in your tuples, and just join:

a = ((1,1,1),)
for i in range(2,10):
    a = a + ((i,i,i),)

Edit: Adapting juanpa.arrivillaga's comment, if you want to stick with a loop, this is the right solution:

a = [(1,1,1)]
for i in range (2,10):
    a.append((i,i,i))
a = tuple(a)

回答2:

You can declare it without having to use a loop.

a = tuple((i,)*3 for i in range(1, 10))

回答3:

itertools.repeat can also be used here:

>>> from itertools import repeat
>>> [tuple(repeat(i, 3)) for i in range(1, 10)]
[(1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4), (5, 5, 5), (6, 6, 6), (7, 7, 7), (8, 8, 8), (9, 9, 9)]

If you want the final result to be in a tuple of tuples instead of a list of tuples, you can wrap tuple again:

>>> tuple(tuple(repeat(i, 3)) for i in range(1, 10))
((1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4), (5, 5, 5), (6, 6, 6), (7, 7, 7), (8, 8, 8), (9, 9, 9))

回答4:

A tuple is an immutable list. It means once you create a tuple, it cannot be modified. Read more about tuples and other sequential data types here, https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences. So, if you really need to change a tuple during run time:

Convert the tuple into a list
Make the necessary changes to the list
Convert the list back to a tuple

Create a list
Modify the list
Convert the list into a tuple

So, in your case:

a = []
for i in range (1,10):
    a.append((i,i,i))
a = tuple(a)   
print a

回答5:

If I were to imitate something like this, I would have done it in the following way:

a = tuple((n,n,n) for n in range(1,10))
print(a)

#((1, 1, 1), (2, 2, 2), (3, 3, 3), (4, 4, 4), (5, 5, 5), (6, 6, 6), (7, 7, 7), (8, 8, 8), (9, 9, 9))

This is the most simple and pythonic way to do this specific job.

回答6:

A little experimentation got this working. I guess you need a comma after the tuple in a to convince python it is a tuple.

a = ((1,1,1),)
for i in range(2, 10):
  a = a + ((i,i,i),)

print(a)

来源：https://stackoverflow.com/questions/48837384/how-to-create-tuple-with-a-loop-in-python

标签

python

for-loop

tuples