Python, how to trim a list in an array

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If I understood you problem (and I'm not at all sure I did), this is the solution:

result = []
for i in range(0,len(arr[0]), 3):
     result.extend( [ arr[0][i:i+3], arr[1][i:i+3] ] )

Besides, as already pointed out in the comments, your input data would be more readable if put this way:

arr = [ 
          [211, 211, 211, 132, 132, 132], # these are x values
          [47, 47, 47, 66, 66, 66]        # and these are y's
      ]

Python, Python | Truncate a list. Last Updated: 04-01-2019. Sometimes there is a requirement to restrict the list size to a particular number and remove all the elements� To trim a list in place without creating copies of it, use del: >>> t = [1, 2, 3, 4, 5] >>> # delete elements starting from index 4 to the end >>> del t[4:] >>> t [1, 2, 3, 4] >>> # delete elements starting from index 5 to the end >>> # but the list has only 4 elements -- no error >>> del t[5:] >>> t [1, 2, 3, 4] >>>. share.

Use slicing

    [ [arr[0][:3], arr[1][:3]], [arr[0][3:], arr[1][3:]] ]

How to Slice Lists/Arrays and Tuples in Python, So you've got an list, tuple or array and you want to get specific sets of sub- elements from it, without any long, drawn out for loops? Python has� The original list is : [1, 4, 5, 6, 7, 3, 8, 9, 10] The truncated list is : [1, 4, 5, 6, 7] Method #2 : Using del + list slice. del operator can be used to delete all the elements that appear after the specific index, which is handled by the list slicing technique. filter_none.

Ok, so you have 2 sublists each sequentially composed of triplets, and you want to build a new list containing pairs built from the triplets from both sublist.

In Python is could be written as:

Remove Elements From Lists | Python List remove() Method, How do I remove the first element from a list in Python? list.pop() – The simplest approach is to use list's pop([i]) method which removes and returns an item present at the specified position in the list. list.remove() – Slicing – The del statement – Reshaping arrays. Reshaping means changing the shape of an array. The shape of an array is the number of elements in each dimension. By reshaping we can add or remove dimensions or change number of elements in each dimension.

Python List remove(), The remove() method removes the first matching element (which is passed as an argument) from the list. Python Slicing | Reverse an array in groups of given size; Move all zeroes to end of array using List Comprehension in Python; K’th Non-repeating Character in Python using List Comprehension and OrderedDict; Python | Check if all the values in a list that are greater than a given value; Print anagrams together in Python using List and Dictionary

Python Remove Array Item, You can use the pop() method to remove an element from the array. Note: The list's remove() method only removes the first occurrence of the specified value. I interpret the 'divide a list in half' to be .. (i.e. two lists only and there shall be no spillover to a third array in case of an odd one out etc). For instance, if the array length is 19 and a division by two using // operator gives 9, and we will end up having two arrays of length 9 and one array (third) of length 1 (so in total three arrays).

There are many ways of clearing the list through methods of different constructs offered by Python language. Let’s try to understand each of the method one by one. Method #1 : Using clear () method. filter_none.

Comments

arr is not a valid python list
Do you just need the first three elements in each sublist i.e. [sublist[:3] for sublist in arr]?
Why is arr not a valid python list? @ncica
@Wimanicesir eg 211x is invalid syntax
Adding the char didn't make the example clearer in any way.