Change specific component in nested list from string to float

Question

I have a nested list of strings. I want to change the first component of the nested list to integer, second to float.

>>> mylist = [['1','2','3'],['5','6','7']]
>>> datl3 = [[int(x) for x in line[0]] + line[1:] for line in mylist]
>>> type(datl3[0][0])
<type 'int'>
>>> 
>>> # turn second element to float
... datl4 = [line[0] + [float(x) for x in line[1]] + line[2] for line in datl3]
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
TypeError: unsupported operand type(s) for +: 'int' and 'list'

How I can I change the second component to float?

juanpa.arrivillaga · Accepted Answer · 2018-09-29 23:27:14Z

2

You can use fancy unpacking to do this:

>>> mylist = [['1','2','3'],['5','6','7']]
>>> [[int(first),float(second),*rest] for first, second, *rest in mylist]
[[1, 2.0, '3'], [5, 6.0, '7']]

answered Sep 29, 2018 at 23:27

juanpa.arrivillaga

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vash_the_stampede · Accepted Answer · 2018-10-01 01:11:35Z

0

Using list comprehension

l = [[int(i[0]), float(i[1]), i[2]] for i in l]

[[1, 2.0, '3'], [5, 6.0, '7']]

answered Oct 1, 2018 at 1:11

vash_the_stampede

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