Python3 get error when constructing a map object by list constructor
Question:
list_of_input = map(float,[1,2,3])
print(list(list_of_input)[0])
print(list(list_of_input)[0])
IndexError: list index out of range
Why does this error occur?
Answers:
The conversion of a map to list is done only once, meaning map is a generator object and once you transform it to list, it gets exhausted : python 3: generator for map. So the error comes from second print statement and not the first.
in Python 3 map() returns an iterator not a list. When you pass this iterator to list the first time it consumes the iterator so the second time you get an empty list, hence the IndexError.
list_of_input = map(float,[1,2,3])
print(list(list_of_input)[0])
print(list(list_of_input)[0])
IndexError: list index out of range
Why does this error occur?
The conversion of a map to list is done only once, meaning map is a generator object and once you transform it to list, it gets exhausted : python 3: generator for map. So the error comes from second print statement and not the first.
in Python 3 map() returns an iterator not a list. When you pass this iterator to list the first time it consumes the iterator so the second time you get an empty list, hence the IndexError.