使用 for 循环从列表创建过滤列表

Question

I want to create a function which creates a new List from a List with a for loop. In the new List should just be int and float in a range from 1 to 49.

Like:

filter_list[2,3,55,"test",10]=[2,3,10]

how can i create such a list with a for loop?

Edit: My code so far:

def filter_list(elements):
    list = []
    for i in elements:
        if i in range(1,50):
            list.append(i)
    return list

but when i want to proof if its int or float with

isinstance(i,str)

it does not work probably

Answer 1

You could use filter :

def filter_list(l):
    return list(filter(lambda x: (isinstance(x, int) or isinstance(x, float)) and 1 <= x <= 49, l))

For python2, you won't need to convert the result of filter to a list. But for python3, you'll need the conversion.

And you'll call it this way:

>>> filter_list([2,3,55,"test",10])
[2, 3, 10]

Or simply use a list comprehension:

def filter_list(l):
    return [x for x in l if (isinstance(x, int) or isinstance(x, float)) and 1 <= x <= 49]