将List转换为Dictionary并使用List Comprehension将其值和键转换为整数

Question

suppose we have a list of list called A :

A = [['1', '200'], ['2', '450'], ['3', '300']]

What I want to do are convert list of lists above into a dictionary with first element as key and second as value, and after that I want to make both of keys and values converted to integer.

So it will be as follows:

A = {1: 200, 
     2: 450,
     3: 300}

With all keys and values are integer.

I tried list comprehension for this:

A = dict(zip(int(a), int(b)) for a, b in row for row in A) 

Got error on it:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'row' is not defined

Answer 1

You don't need zip() here, just drop that, and you can loop directly over A and unpack into a and b :

A = dict((int(a), int(b)) for a, b in A)

That's a generator expression passing tuples to the dict() callable.

If you can, you want to use a dictionary comprehension instead; that's available in Python 2.7 and newer (including all Python 3.x releases):

A = {int(a): int(b) for a, b in A}

Demo:

>>> A = [['1', '200'], ['2', '450'], ['3', '300']]
>>> dict((int(a), int(b)) for a, b in A)
{1: 200, 2: 450, 3: 300}
>>> {int(a): int(b) for a, b in A}
{1: 200, 2: 450, 3: 300}

Answer 2

A = [['1', '200'],['2', '450'],['3','300']]
B_dict = {int(i[0]): int(i[1]) for i in A}