The PEP, titled Additional Unpacking Generalizations, generally reduced some syntactic restrictions when using the starred * expression in Python; with it, joining two lists (applies to any iterable) can now also be done with:

Sep 10, 2013 · # Pythonic approach leveraging map, operator.add for element-wise addition. import operator third6 = list(map(operator.add, first, second)) # v7: Using list comprehension and range-based indexing # Simply an element-wise addition of two lists.

In this question your code gets two lists of molecular weights. Print: The second lowest molecular weight for each list (2 numbers) The average molecular weight for the two lists together (single number) Make a new list that includes all the elements from both lists, except for the maximum and minimum values (all values from the two list except 2 values).

Jul 28, 2012 · @Xion Wrong, that's not readable at all compared to a list comprehension and should only be used as a form of micro-optimization if dealing with a very large dataset where map(add, list1, list2) will perform much faster. However in this …

I've looked up the official Python tutorial but couldn't find anything anything about this topic. This information happens to be buried in the Programming FAQ:... for lists, __iadd__ [i.e. +=] is equivalent to calling extend on the list and returning the list. That's why we say that for lists, += is a "shorthand" for list.extend

Jun 11, 2013 · What is the fastest way to achieve the following in python? list = [1,2,3,4,5,6,7,8] Please note that there can be many ways to merge two lists in python. I am looking for the most time-efficient way. I tried the following and here is my understanding. CODE

@Full Decent, thanks for point this out, did not think about that i=n case. But I think if it is i=n case, can loop in the lists and concatenate them. For me, just need the most comma way to join 2 lists without duplication elements. –

How do I take multiple lists and put them as different columns in a python dataframe? I tried this solution but had some trouble. Attempt 1: Have three lists, and zip them together and use that res = zip(lst1,lst2,lst3) Yields just one column; Attempt 2:

Apr 4, 2013 · If the lists are big you should use itertools.izip. If you have more keys than values, and you want to fill in values for the extra keys, you can use itertools.izip_longest . Here, a , b , c , and d are variables -- it will work fine (so long as they are defined), but you probably meant ['a','b','c','d'] if you want them as strings.

I think, this answer should get more credit. If one has variable number of lists. Let's say in data preparation you have positives and negatives (user can define the number of negatives), then the above solution will solve this issue with variable number of negatives list.