python快速排序算法实现 'int' object is not iterable

Answer 1

Thank you araraloren!
Oh, I found the error. A low-level error: return quicksort(forehalf)+list(numbers[0])+quicksort(endhalf), list(numbers[0]) is illegal, it should be: return quicksort(forehalf)+[numbers[0]]+ quicksort(endhalf)