Python Forum

Hi,
is there a faster way of changing s list full of numbers in a "5" format, into a int(5) format than:

for i in range(len(a)):
a[i]=int(a[i])

The "" format you mean, is a str.

If you have this list with strings:

some_values = ["1", "-5", "10", "-15"]

You can cast the str to int with different methods.

Some examples:

# the values defined here
some_values = ["1", "-5", "10", "-15"]

# list comprehension
new_some_values_1 = [int(value) for value in some_values]

# classical for-loop
new_some_values_2 = [] # empty list
for value in some_values:
    value = int(value)
    new_some_values_2.append(value)

# functional style with map
# each element of some_values is called with int()
# the list consumes the resulting map object
# it's lazy evaluated, not consuming the map object -> no values
new_some_values_3 = list(map(int, some_values))


# generator expression + for-loop
values = (int(value) for value in some_values)
for value in values: # <- evaluation of the generator begins here
    print(value, type(value)) # <- printing the value and type of value
# now values is consumed
# you can't use it again because it's now empty

But what I'm talking about is that the user types the numbers in 1 line:
3 5 7 2 53 2
and not:
23
5
7
2
53
2

I have it like this now:
t.extend(input().split())

One way is to use list comprehension:

>>> data = input('Enter number separated by space: ')
Enter number separated by space: 23 4 5 6 7
>>> [int(entry) for entry in data.split()]
[23, 4, 5, 6, 7]

(Dec-04-2020, 10:44 AM)1234 Wrote: [ -> ]But what I'm talking about is that the user types the numbers in 1 line

The solution provided perfringo.

The only problem is the user itself. The user could make mistakes during entering the numbers.
If there is for example one accidental comma in the user-input, int(entry) will raise a ValueError.

Just saying, don't trust users input.