My answer is not exactly to your question but after you read this, I hope you can decide which type you need to choose for your needs.
Python’s lists are variable-length arrays, not Lisp-style linked lists. The implementation uses a contiguous array of references to other objects, and keeps a pointer to this array.
This makes indexing a list a[i] an operation whose cost is independent of the size of the list or the value of the index.
When items are appended or inserted, the array of references is resized. Some algorithm is applied to improve the performance of appending items repeatedly; when the array must be grown, some extra space is allocated so the next few times don’t require an actual resize i.e over-allocation. More Information
Removing vs Pop vs Delete:
At first glance it looks like all of them are doing the same thing.
Under the hood its behaving different.
removing : remove an element from the list by iterating from 0 index till the first match of the element is found. taking more time to iterate if the element is at the end.
pop : removing element from the list by using the index. taking less time.
del : is a python statement that removes a name from a namespace, or an item from a dictionary, or an item from a list by using the index.
REMOVE:
- it removes the first occurence of value.
- raises ValueError if the value is not present.
- it takes only one argument, so you can't remove multiple value in one shot.
POP:
- remove and return item at index (default last).
- Raises IndexError if list is empty or index is out of range.
- it takes only one argument, so you can't remove multiple value in one shot.
DEL:
- remove the item at index and return nothing.
- it can remove slices from a list or can clear the whole list.
Benchmark:
Worst case : deleting from the end of the list.
yopy:-> python -m timeit "x=range(1000)" "x.pop(999)"
100000 loops, best of 3: 10 usec per loop
yopy:-> python -m timeit "x=range(1000)" "x.remove(999)"
10000 loops, best of 3: 31.3 usec per loop
yopy:-> python -m timeit "x=range(1000)" "del x[999]"
100000 loops, best of 3: 9.86 usec per loop
yopy:->
Best case: begining of the list.
yopy:-> python -m timeit "x=range(1000)" "x.remove(1)"
100000 loops, best of 3: 10.3 usec per loop
yopy:-> python -m timeit "x=range(1000)" "x.pop(1)"
100000 loops, best of 3: 10.4 usec per loop
yopy:-> python -m timeit "x=range(1000)" "del x[1]"
100000 loops, best of 3: 10.4 usec per loop
yopy:->
Point to be noted:
if array grows or shrinks in the middle
- Realloc still depends on total length.
- But, All the trailing elements have to be copied
So, now I hope you can decide what you need to choose for your needs.
Answer from James Sapam on Stack OverflowNeed advice on how to completely uninstall python
python - Best way to remove elements from a list - Stack Overflow
installation - How to completely remove Python from a Windows machine? - Stack Overflow
Could you pls tell me how to uninstall python 3.12.4(64 bit)
Videos
so im on win10 and running python 3.8.3 and my pip suddenly stopped working and couldnt get it to work anymore. i tried lots of things but sadly nothing .
so i would like to completely remove python ( and the cache or whatever will be scattered or left behind by the installer) . anyone can help me on this
My answer is not exactly to your question but after you read this, I hope you can decide which type you need to choose for your needs.
Python’s lists are variable-length arrays, not Lisp-style linked lists. The implementation uses a contiguous array of references to other objects, and keeps a pointer to this array.
This makes indexing a list a[i] an operation whose cost is independent of the size of the list or the value of the index.
When items are appended or inserted, the array of references is resized. Some algorithm is applied to improve the performance of appending items repeatedly; when the array must be grown, some extra space is allocated so the next few times don’t require an actual resize i.e over-allocation. More Information
Removing vs Pop vs Delete:
At first glance it looks like all of them are doing the same thing.
Under the hood its behaving different.
removing : remove an element from the list by iterating from 0 index till the first match of the element is found. taking more time to iterate if the element is at the end.
pop : removing element from the list by using the index. taking less time.
del : is a python statement that removes a name from a namespace, or an item from a dictionary, or an item from a list by using the index.
REMOVE:
- it removes the first occurence of value.
- raises ValueError if the value is not present.
- it takes only one argument, so you can't remove multiple value in one shot.
POP:
- remove and return item at index (default last).
- Raises IndexError if list is empty or index is out of range.
- it takes only one argument, so you can't remove multiple value in one shot.
DEL:
- remove the item at index and return nothing.
- it can remove slices from a list or can clear the whole list.
Benchmark:
Worst case : deleting from the end of the list.
yopy:-> python -m timeit "x=range(1000)" "x.pop(999)"
100000 loops, best of 3: 10 usec per loop
yopy:-> python -m timeit "x=range(1000)" "x.remove(999)"
10000 loops, best of 3: 31.3 usec per loop
yopy:-> python -m timeit "x=range(1000)" "del x[999]"
100000 loops, best of 3: 9.86 usec per loop
yopy:->
Best case: begining of the list.
yopy:-> python -m timeit "x=range(1000)" "x.remove(1)"
100000 loops, best of 3: 10.3 usec per loop
yopy:-> python -m timeit "x=range(1000)" "x.pop(1)"
100000 loops, best of 3: 10.4 usec per loop
yopy:-> python -m timeit "x=range(1000)" "del x[1]"
100000 loops, best of 3: 10.4 usec per loop
yopy:->
Point to be noted:
if array grows or shrinks in the middle
- Realloc still depends on total length.
- But, All the trailing elements have to be copied
So, now I hope you can decide what you need to choose for your needs.
Use a list comprehension:
Scenario 1:
[item for item in my_list if 1 <= item <=5 ]
Scenario 2:
to_be_removed = {'a', '1', 2}
[item for item in my_list if item not in to_be_removed ]
Scenario 3:
[item for item in my_list if some_condition()]
Scenario 4(Nested list comprehension):
[[item for item in seq if some_condition] for seq in my_list]
Note that if you want to remove just one item then list.remove, list.pop and del are definitely going to be very fast, but using these methods while iterating over the the list can result in unexpected output.
Related: Loop “Forgets” to Remove Some Items
Here's the steps (my non-computer-savvy girlfriend had to figure this one out for me, but unlike all the far more complicated processes one can find online, this one works)
- Open Control Panel
- Click "Uninstall a Program"
- Scroll down to Python and click uninstall for each version you don't want anymore.
This works on Windows 7 out of the box, no additional programs or scripts required.
You will also have to look in your system path. Python puts itself there and does not remove itself: http://www.computerhope.com/issues/ch000549.htm
Your problems probably started because your python path is pointing to the wrong one.
Here's a nice Pythonic way to do it using list comprehensions and enumerate (note that enumerate is zero-indexed):
>>> y = [3,4,5,6]
>>> [x for i, x in enumerate(y) if i != 1] # remove the second element
[3, 5, 6]
The advantage of this approach is that you can do several things at once:
>>> # remove the first and second elements
>>> [x for i, x in enumerate(y) if i != 0 and i != 1]
[5, 6]
>>> # remove the first element and all instances of 6
>>> [x for i, x in enumerate(y) if i != 0 and x != 6]
[4, 5]
Use list.pop:
>>> a = [1,2,3,4]
>>> a.pop(2)
3
>>> a
[1, 2, 4]
According to the documentation:
s.pop([i])
same as x = s[i]; del s[i]; return x
UPDATE
For chaining, you can use following trick. (using temporary sequence that contains the original list):
>>> a = [1,2,3,4]
>>> [a.pop(2), a][1] # Remove the 3rd element of a and 'return' a
[1, 2, 4]
>>> a # Notice that a is changed
[1, 2, 4]