在 Python 中将浮点数列表四舍五入为整数

Question

I have a list of numbers which I need to round into integers before I continue using the list. Example source list:

[25.0, 193.0, 281.75, 87.5, 80.5, 449.75, 306.25, 281.75, 87.5, 675.5,986.125, 306.25, 281.75]

What would I do to save this list with all of the numbers rounded to an integer?

Answer 1

Simply use round function for all list members with list comprehension :

myList = [round(x) for x in myList]

myList # [25, 193, 282, 88, 80, 450, 306, 282, 88, 676, 986, 306, 282]

If you want round with certain presicion n use round(x,n) :

Answer 2

You could use the built-in function round() with a list comprehension:

newlist = [round(x) for x in list]

You could also use the built-in function map() :

newlist = list(map(round, list))

I wouldn't recommend list as a name, though, because you are shadowing the built-in type.

Answer 3

If you would set the number of significant digits you could do

new_list = list(map(lambda x: round(x,precision),old_list))

Furthermore, if you had a list of list you could do

new_list = [list(map(lambda x: round(x,precision),old_l)) for old_l in old_list]

Answer 4

Another approach using map function.

You can set how many digits to round .

>>> floats = [25.0, 193.0, 281.75, 87.5, 80.5, 449.75, 306.25, 281.75, 87.5, 675.5,986.125, 306.25, 281.75]
>>> rounded = map(round, floats)
>>> print rounded
[25.0, 193.0, 282.0, 88.0, 80.0, 450.0, 306.0, 282.0, 88.0, 676.0, 986.0, 306.0, 282.0]

Answer 5

You can use python's built in round function.

l = [25.0, 193.0, 281.75, 87.5, 80.5, 449.75, 306.25, 281.75, 87.5, 675.5,986.125, 306.25, 281.75]

list = [round(x) for x in l]

print(list)

The output is:

[25, 193, 282, 88, 80, 450, 306, 282, 88, 676, 986, 306, 282]

Answer 6

NumPy is great for handling arrays like this.
Simply np.around(list) or np.round(list) works.

Answer 7

Updating this for python3 since other answers leverage python2's map , which returns a list , where python3's map returns an iterator. You can have the list function consume your map object:

l = [25.0, 193.0, 281.75, 87.5, 80.5, 449.75, 306.25, 281.75, 87.5, 675.5,986.125, 306.25, 281.75]

list(map(round, l))
[25, 193, 282, 88, 80, 450, 306, 282, 88, 676, 986, 306, 282]

To use round in this way for a specific n , you'll want to use functools.partial :

from functools import partial

n = 3
n_round = partial(round, ndigits=3)

n_round(123.4678)
123.468

new_list = list(map(n_round, list_of_floats))