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# Drop first element of list of lists, condense list of lists? Too many elements?

By : DoomsDayDave
Date : October 19 2020, 08:10 AM
this will help The object shown in the question is not a list of lists of 4 data frames each so if we call that object L then to get what is described we need to create LL like this. Now using LL we can compute the 3 items requested.
code :
``````LL <- list(L[1:4], L[5:8])

res1 <- sapply(LL, function(x) nrow(x\$Comm))
res2 <- lapply(LL, function(x) x[names(x) != "Comm"])
res3 <- lapply(LL, function(x) do.call("rbind", x[names(x) != "Comm"]))
``````

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## Convert list of strings into list of lists with each element in list of lists as each iterable letter in string. All in

By : rouraito
Date : March 29 2020, 07:55 AM
wish of those help With list of strings x: , With list and simple list comprehension:
code :
``````>>> x = ['foo', 'bar']
>>> y = [list(word) for word in x]
>>> y
[['f', 'o', 'o'], ['b', 'a', 'r']]
``````
``````>>> y = map(list, x)
>>> y
[['f', 'o', 'o'], ['b', 'a', 'r']]
``````

## In python, trying to combine elements from a list of lists into a new list of combined-element lists

By : Claudiu
Date : March 29 2020, 07:55 AM
seems to work fine I am a python newbie.
code :
``````result = map(list, zip(*test))
``````

## Assigning element of list of lists by index sets all first elements of the lists

By : Cesar Mu
Date : March 29 2020, 07:55 AM
may help you . When you do this v=[[0.0,0.0,0.0]]*12 you are getting a list with 12 references to the same list, to fix that use a comprehension instead:
code :
``````v = [[0.0,0.0,0.0] for _ in range(12)]
``````

## Python - Summing elements on list of lists based on first element of inner lists

By : MarwanMR1
Date : March 29 2020, 07:55 AM
code :
``````>>> from collections import defaultdict
>>> data = defaultdict(int)
>>> L = [[0.5, 2], [0.5, 5], [2, 3], [2, 6], [2, 0.6], [7, 1]]
>>> for k, v in L:
...     data[k] += v
...
>>> [[k,v] for (k,v) in data.items()]
[[0.5, 7], [2, 9.6], [7, 1]]
``````

## Is there any easy way to add elements in lists in a list to make all lists in a list has a same number of element?

By : user2606562
Date : March 29 2020, 07:55 AM
Hope this helps Honestly, I didn't find out for this question cuz... I don't know how to search or google it. So it might be the basic problem, but if anyone can helps me, I would really appreciate it. , Using zip with itertools.zip_longest:
code :
``````import itertools

list(zip(*itertools.zip_longest(*results, fillvalue='')))
``````
``````[(1, 2, 3, '', '', '', '', ''),
(1, 2, 3, 4, '', '', '', ''),
(1, 2, 3, 4, 5, 6, 7, 8)]
``````