How to combine two lists

Question

I can write the append line two ways. Neither produce the desired result. Is there a way to wrap this up in 1 line?

Option 1:

row.append(x[1] for x in emails if x[0] == row[1]) 

Yields:

[['project1', 'email1', <generator object <genexpr> at 0x0227D670>], ['project1', 'email2', <generator object <genexpr> at 0x022EB8A0>]]

Option 2:

row.append([x[1] for x in emails if x[0] == row[1]]) 

Yields:

[['project1', 'email1', ['john@gmail.com']], ['project1', 'email2', ['bill@gmail.com']]]

Desired Result:

[['project1', 'email1', 'john@gmail.com'], ['project1', 'email2', 'bill@gmail.com']]

Code:

emails = [['email1','john@gmail.com'],['email2','bill@gmail.com']]

projects = [['project1', 'email1'], ['project1', 'email2']]

for row in projects:
    row.append(x[1] for x in emails if x[0] == row[1])
print projects

Answer 1

In your existing code, replace this one line:

row.append(x[1] for x in emails if x[0] == row[1])

With:

row.extend(x[1] for x in emails if x[0] == row[1])

One-line solution

Alternatively, eliminating the loop and condensing the code all into one line:

>>> projects = [  row + [x[1] for x in emails if x[0] == row[1]] for row in projects ]
>>> print projects 
[['project1', 'email1', 'john@gmail.com'], ['project1', 'email2', 'bill@gmail.com']]

Answer 2

emails = [['email1','john@gmail.com'],['email2','bill@gmail.com']]

projects = [['project1', 'email1'], ['project1', 'email2']]
from itertools import chain


print([list(set((chain.from_iterable(ele)))) for ele in zip(emails,projects)])
[['email1', 'john@gmail.com', 'project1'], ['email2', 'project1', 'bill@gmail.com']]

Or:

print([list(set(ele).union(projects[ind])) for ind, ele in enumerate(emails)])

Or:

print([projects[ind] + [ele for ele in sub if ele not in projects[ind]] for ind, sub in enumerate(emails)])

All the different versions will work for multiple items not just checking against a single element.