How to fill a tuple with a for loop

Question

I am trying to fill a tuple with named tuples using a for loop.

The example code below works:

import collections

Experiment = collections.namedtuple('Experiment', ['parameter', ])

nsize = 3

parameters = {}
for n in range(0, nsize):
    parameters[n] = n +1
   

experiments = (
        Experiment(parameter = parameters[0]),   
        Experiment(parameter = parameters[1]),
        Experiment(parameter = parameters[2]),)

However, I would like to replace the last section with a for loop:

for n in range(0, nsize):
    experiments[n] = Experiment(parameter = parameters[n])

Which gives the error:

TypeError: 'tuple' object does not support item assignment

Any ideas?

Aren't tuples immutable? In that case, it makes sense that you can't change it. — M-Chen-3, Dec 08 '20 at 16:36
If the indices of `parameters` really is just a set of continuous integers from 0 to `nsize - 1`, consider using a list instead. `parameters = list(range(1,nsize+1))`. Then Mark Meyer's answer becomes simply `tuple(Experiment(x) for x in parameters)`. — chepner, Dec 08 '20 at 16:47
Does this answer your question? [How to fix a : TypeError 'tuple' object does not support item assignment](https://stackoverflow.com/questions/19338209/how-to-fix-a-typeerror-tuple-object-does-not-support-item-assignment) — Tomerikoo, Dec 08 '20 at 16:52

score 5 · Accepted Answer · answered Dec 08 '20 at 16:40

Tuples are immutable, so you can't modify them after creating them. If you need to modify the data structure, you'll need to use a list.

However, instead of using a for loop, you can pass a generator expression to tuple() and make the tuple all at once. This will give you both the tuple you want and a way to make it cleanly.

import collections

Experiment = collections.namedtuple('Experiment', ['parameter', ])

nsize = 3

parameters = {}
for n in range(0, nsize):
    parameters[n] = n + 1
    
expirements = tuple(Experiment(parameter = parameters[n]) for n in range(nsize))
# (Experiment(parameter=1), Experiment(parameter=2), Experiment(parameter=3))

This works great, thanks for the super quick reply! – coccolith Dec 08 '20 at 16:53 — coccolith, Dec 08 '20 at 16:53

score 0 · Answer 2 · answered Dec 08 '20 at 16:38

0

Tuple are immutable, you should consider changing it to a list.

answered Dec 08 '20 at 16:38

SDTbone

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score 0 · Answer 3 · answered Dec 08 '20 at 16:45

0

Since tuples are immutable, you can convert tuples to something mutable, do you stuff and then convert it back to tuples using tuple () function

answered Dec 08 '20 at 16:45

Just don't be user123

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How to fill a tuple with a for loop

3 Answers3