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I want to "weave" two numberrows together.

Example:

x = [1,2,3]
y = [4,5,6]

result = [1,4,2,5,3,6]

This is my function, I can't find out why it doesn't work:

def weave(list1,list2):
    lijst = []
    i = 0
    for i <= len(list1):
        lijst += [list1[i]] 
        lijst += [list2[i]] 
        i + 1

Python, Python's for-loops aren't like other languages where you can have a conditional. You need to use a while loop instead or alter your for-loop: def weave(list1� Your __weave_element_into_list() has a scalability problem: inserting elements into the middle of a list requires a lot of work to shift all subsequent items. The weave() function proposed in Rev 2 of @janos's answer involved even more copying, since tuples are immutable; the revision in Rev 3 has much better performance characteristics. Benchmark:

You can use the chain function from itertools module to interleave two lists:

x = [1,2,3]
y = [4,5,6]

from itertools import chain
list(chain.from_iterable(zip(x, y)))
# [1, 4, 2, 5, 3, 6]

Python: shortest way to interleave items from two lists, map() is used to handle the interleave of lists and the task of insertion at alternate is performed by the list comprehension part of the shorthand� I am new to python (sort of), anyway I am not sure why this is not working. Should be simple to weave two lists together with a boolean pattern of true false. I don’t really understand how to flatten the two lists after using python’s built in ‘zip’ function. import rhinoscriptsyntax as rs list1 = [] list2 = [] list3 = [] for x in range (0,20,2): y = 0 z = 0 ptlist1 = rs.AddPoint(x,y,z

You can also weave lists by defining the even and odd half-lists of the result list.

x = [1,2,3]
y = [4,5,6]

z = numpy.empty(len(x)+len(y))
z[::2],z[1::2]=x,y

result=z.tolist()

Need Help With Weaving Of Lists, Zip and Sum. [*sum(zip(l2,l1),())]. Try it online! Zips the two lists together then adds all the tuples to make one combined list. The zip only works� The weave.inline() function executes C code directly within Python, and weave.blitz() translates Python NumPy expressions to C++ for fast execution. blitz() was the original reason weave was built. For those interested in building extension libraries, the ext_tools module provides classes for building extension modules within Python.

Weave lists of pts together - Scripting, So the "weaving" indicates that you want alternating entries from each list, followed by the tail of the longer list? Probably the most basic� Zips the two lists together then adds all the tuples to make one combined list. The zip only works if the lists are guaranteed to be the same size, otherwise it truncates the longer list. Added the surrounding [* ] to transform it into a list as FryAmTheEggman suggests.

>>> x = [1,2,3]
>>> y = [4,5,6]
>>> z=[]
>>> for i,j in zip(x,y):
...    z.extend([i,j])
... 
>>> z
[1, 4, 2, 5, 3, 6]

Solved: You Must Write A Function Zip() That Weaves Two Li , Should be simple to weave two lists together with a boolean pattern of true false. I don't really understand how to flatten the two lists after using python's built in 'zip � List Comprehensions are one of the most amazing features of Python. It is a smart and concise way of creating lists by iterating over an iterable object. Nested List Comprehensions are nothing but a list comprehension within another list comprehension which is quite similar to nested for loops.

Weave (scipy.weave) — SciPy v0.14.0 Reference Guide, You must write a function zip() that weaves two lists of the same length. input list and adds it to the end of the list that extend was called on. linux[0]$ python� Questions: In Python, is there a good way to interleave two lists of the same length? Say I’m given [1,2,3] and [10,20,30]. I’d like to transform those into [1,10,2,20,3,30]. Answers: Having posted the question, I’ve realised that I can simply do the following: [val for pair in zip(l1, l2) for val in pair] where l1

Recursion (Part 1), c_code is a string of valid C/C++ code. var_list is a list of variable names that are passed from Python into C/C++. Here we have a simple printf statement that� Given lists of same length, write a Python program to store alternative elements of given lists in a new list. Let’s discuss certain ways in which this can be performed. Method #1 : Using map() + list comprehension

Recursion help! : learnpython, return [list1[0] , list2[0]] + interleave(list1[1:], list2[1:]) print interleave([1,2,3] interleave with different-length lists B) Turn into Python (The "magic" is recursion!) Weave is the stand-alone version of the deprecated Scipy submodule scipy.weave. It is Python 2.x only, and is provided for users that need new versions of Scipy (from which the weave submodule may be removed) but have existing code that still depends on scipy.weave. For new code, users are recommended to use Cython.

Comments
  • for i <= is not of the Python world.
  • Related: interleaving 2 lists of unequal lengths
  • You are using for instead of while
  • I would add a strong encouragement to use itertools and similar operations on iterables whenever you are faced with lists of stuff to manipulate in Python. It is far more robust, and far more readable.