pop remove items out of a python tuple

Question

I am not sure if I can make myself clear but will try   I have a tuple in python which I go through as follows  see code below   While going through it  I maintain a counter  let s call it  n   and  pop  items that meet a certain condition   Now of course once I pop the first item  the numbering all goes wrong  how can I do what I want to do more elegantly while removing only certain entries of a tuple on the fly   for x in tupleX    n 0   if  condition        tupleX pop n    n n 1

User · Answer

There is a simple but practical solution.

As DSM said, tuples are immutable, but we know Lists are mutable. So if you change a tuple to a list, it will be mutable. Then you can delete the items by the condition, then after changing the type to a tuple again. That’s it.

Please look at the codes below:

tuplex = list(tuplex)
for x in tuplex:
  if (condition):
     tuplex.pop(tuplex.index(x))
tuplex = tuple(tuplex)
print(tuplex)

For example, the following procedure will delete all even numbers from a given tuple.

tuplex = (1, 2, 3, 4, 5, 6, 7, 8, 9)
tuplex = list(tuplex)
for x in tuplex:
  if (x % 2 == 0):
     tuplex.pop(tuplex.index(x))
tuplex = tuple(tuplex)
print(tuplex)

if you test the type of the last tuplex, you will find it is a tuple.

Finally, if you want to define an index counter as you did (i.e., n), you should initialize it before the loop, not in the loop.

User · Answer

As DSM mentions  tuple s are immutable  but even for lists  a more elegant solution is to use filter   tupleX   filter str isdigit  tupleX    or  if condition is not a function  use a comprehension   tupleX    x for x in tupleX if x  gt  5    if you really need tupleX to be a tuple  use a generator expression and pass that to tuple   tupleX   tuple x for x in tupleX if condition

User · Answer

Yes we can do it  First convert the tuple into an list  then delete the element in the list after that again convert back into tuple   Demo   my tuple    10  20  30  40  50     converting the tuple to the list my list   list my tuple  print my list    output   10  20  30  40  50     Here i wanna delete second element  20  my list pop 1    output   10  30  40  50    As you aware that pop 1  indicates second position    Here i wanna remove the element  50  my list remove 50    output   10  30  40     again converting the my list back to my tuple my tuple   tuple my list    print my tuple   output   10  30  40    Thanks

User · Answer

The best solution is the tuple applied to a list comprehension  but to extract one item this could work    def pop tuple tuple  n       return tuple  n  tuple n 1    tuple n

User · Answer

say you have a dict with tuples as keys  e g   labels     1 2 0    label 1   you can modify the elements of the tuple keys as follows  formatted labels     elem 0  elem 1   labels elem  for elem in labels   Here  we ignore the last elements

User · Answer

Maybe you want dictionaries   d   dict   i value  for i value in enumerate tple   while d      bla bla bla     del b x

User · Answer

In Python 3 this is no longer an issue  and you really don t want to use list comprehension  coercion  filters  functions or lambdas for something like this  Just use popped   unpopped  -1   Remember that it s an immutable  so you will have to reassign the value if you want it to change my tuple   my tuple  -1   Example  gt  gt  gt  foo  3 5 2 4 78 2 1  gt  gt  gt  foo  3  5  2  4  78  2  1  foo  -1   3  5  2  4  78  2

User · Answer

ok I figured out a crude way of doing it   I store the  n  value in the for loop when condition is satisfied in a list  lets call it delList  then do the following       for ii in sorted delList  reverse True       tupleX pop ii    Any other suggestions are welcome too

[python] pop/remove items out of a python tuple

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