I frequently have a list of "pre-zipped" (elements are lists) data. I'm trying to convert each item to an integer (from an input string, usually).
How can I make each element in a complex list into an integer?
I initially attempted a list comprehension:
ls = ["1", "2", ["3", "4", "5"], "6"]
ls = [int(i) for i in ls]
But the int function can't take an iterable, so it breaks on int(["3", "4", "5"])
Looking around, I learned about the map() function, which applies a function to each item in an iterable.
ls = ["1", "2", ["3", "4", "5"], "6"]
print(map(lambda x: int(x), ls))
The above code outputs
<map object at 0x000001A84C46E898>
But when I attempt to convert that to a list, I get an error
ls = ["1", "2", ["3", "4", "5"], "6"]
print(list(map(lambda x: int(x), ls)))
TypeError: int() argument must be a string, a bytes-like object or a number, not 'list'
So that sounds to me like map is passing the int() function the list. I also tried itertools.starmap():
import itertools
ls = ["1", "2", ["3", "4", "5"], "6"]
print(list(itertools.starmap(lambda x: int(x), ls)))
This, however, seems to behave the same as map(): returning a map object that can't be converted to a list.
Help is really appreciated. Thanks!
You can use exeption handling on things that throw on int(thing):
def makeInt(data):
try:
k = int(data)
except ValueError:
k = [makeInt(d) for d in data]
return k
ls = ["1", "2", ["3", "4", "5"], "6"]
t = makeInt(ls)
print(t)
Output:
[1, 2, [3, 4, 5], 6]
This will still fail if you supply non-integer data into your lists.