python2代码转换为python3代码

Answer 1

First split the code according to the structure:
'&'.join(List)
Concatenate the elements in the list into strings with & as intervals.

params.iteritems() is an iterator

lambda is an anonymous function. cmp sort.

Convert to string after sorting.

Convert to py3:
The cmp function is no longer used in python3 and can be rewritten.