pop/remove items out of a python tuple

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

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 > 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)

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

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.

Maybe you want dictionaries?

d = dict( (i,value) for i,value in enumerate(tple))
while d:
    bla bla bla
    del b[x]

Reza K Ghazi

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.

来源：https://stackoverflow.com/questions/21682804/pop-remove-items-out-of-a-python-tuple

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python

tuples