Combining Elements of List of Lists by Index

Combining elements of list of lists by index

You can do:

do.call(Map, c(c, lst))

How to merge elements of two lists at the same index in Python?

One way to do this is to zip the input lists then add them:

a = [['a', 1], ['b', 2], ['c', 3]]
b = [10, 20, 30]

c = [x+[y] for x, y in zip(a, b)]
print(c)  # -> [['a', 1, 10], ['b', 2, 20], ['c', 3, 30]]

combining elements in a list of lists in R

Another base R option using paste

do.call(paste, c(data.frame(t(list2DF(samples_ID))), sep = "_"))

or

do.call(paste, data.frame(do.call(rbind, samples_ID)), sep = "_"))

join list of lists in python

import itertools
a = [['a','b'], ['c']]
print(list(itertools.chain.from_iterable(a)))

Merge lists with same first element in list of lists

Try this:

d = {}
for key, value in a:
   if key not in d.keys():
      d[key] = [key]
   d[key].append(value)
result = list(d.values())

Merge python list by specific indexes

Here's an implementation using groupby:

import itertools
x = ["captain:", "robot", "alpha", "beta:", "gama", "delta:", "fighter", "test", "exp"]
new_list = []
for key, group in itertools.groupby(x, key = lambda string: string.endswith(':')):
    if key: # in case you happen to consecutive values that end in a colon
        new_list += list(group)
    else: # these elements do not end in a colon
        new_list.append(', '.join(group))
print(new_list)
# ['captain:', 'robot, alpha', 'beta:', 'gama', 'delta:', 'fighter, test, exp']

Here, the grouping key checks to see if the item ends in a ":", if it does, key is True, otherwise it is False. If consecutive values of key are the same, they are put in the same group. Thus, any number of elements following a string containing a colon will be grouped together.

Merge elements in list of lists

If you don't want to write a loop you can use map and str.join

>>> list(map(''.join, A))
['baaaa', 'baaaa']

However, the loop using a list comprehension is almost as short to write, and I think is clearer:

>>> [''.join(e) for e in A]
['baaaa', 'baaaa']

For each element in list of lists, merge with corresponding value in a separate flat list

Here is a solution you can give it a try,

lst1 = [['a', 'b', 'c'], ['a', 'b', 'c'], ['a', 'b', 'c']]
lst2 = ['x', 'y', 'z']

print(
    [[ii + j for ii in i] for i, j in zip(lst1, lst2)]
)

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[['ax', 'bx', 'cx'], ['ay', 'by', 'cy'], ['az', 'bz', 'cz']]

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