How to sort integers alphabetically

问题

How can I sort integers alphabetically? Like this:

integers = [10, 1, 101, 2, 111, 212, 100000, 22, 222, 112, 10101, 1100, 11, 0]

printed like this on Python console

[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]

I have tried this

def sort_integers(integers):
    return sorted(integers)

but I guess you have to do it this way

def sort_integers(integers):
    return sorted(integers, key = lambda....... )

I just don't know to what to write after the lambda?

回答1:

sorted(integers, key=str)

->
[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]

Explanation: str is a function that casts the integers into strings. Since sorted sorts strings alphabetically by default this does exactly what you asked for.

回答2:

You can simply use str as key:

sorted(integers,key=str)

So here for each element, the str function is called, which converts the int into a string. That itself is not spectacular. But the comparison of strings is different: it sorts lexicographically.

>>> sorted([0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222],key=str)
[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]

回答3:

If you want to sort your integers lexicographically as if they were strings, you can tell Python to treat them as strings while sorting:

>>> integers = [10, 1, 101, 2, 111, 212, 100000, 22, 222, 112, 10101, 1100, 11, 0]
>>> sorted(integers, key=lambda n: str(n))
[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]
>>>

But you actually don't even have to have the lambda n: ... part either. You can simply pass the str function as the key and Python will know what to do. calling str(n) where n is each element in your list:

>>> sorted(integers, key=str)
[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]
>>>

So your function would end up being:

def sort_integers(integers):
    return sorted(integers, key=str)

回答4:

this will work

list(map(int, (sorted(str(i) for i in integers))))

output:

[0, 1, 10, 100000, 101, 10101, 11, 1100, 111, 112, 2, 212, 22, 222]

回答5:

Try a Most Significant Digit Radix Sort. This avoids having to convert the integers to strings, but is tougher to implement unless you use a library or other prewritten code.

来源：https://stackoverflow.com/questions/44835964/how-to-sort-integers-alphabetically

标签

python

sorting

alphabetical-sort