List comprehension on a nested list?

Question

I have this nested list:

l = [[\'40\', \'20\', \'10\', \'30\'], [\'20\', \'20\', \'20\', \'20\', \'20\', \'30\', \'20\'], [\'30\', \'20\', \'30\', \'50\', \'         


        

Answer 1

Here is how to convert nested for loop to nested list comprehension:

Here is how nested list comprehension works:

            l a b c d e f
            ↓ ↓ ↓ ↓ ↓ ↓ ↓
In [1]: l = [ [ [ [ [ [ 1 ] ] ] ] ] ]
In [2]: for a in l:
   ...:     for b in a:
   ...:         for c in b:
   ...:             for d in c:
   ...:                 for e in d:
   ...:                     for f in e:
   ...:                         print(float(f))
   ...:                         
1.0

In [3]: [float(f)
         for a in l
   ...:     for b in a
   ...:         for c in b
   ...:             for d in c
   ...:                 for e in d
   ...:                     for f in e]
Out[3]: [1.0]

For your case, it will be something like this.

In [4]: new_list = [float(y) for x in l for y in x]