在列表理解/映射/过滤器中分配标识符

Question

I want to pass a lambda expression to a filter that captures an outside variable l . I want l to be the list passed to filter. Assume that that list comes out of some other list comprehension/ mapping/ filtering. Is it possible to assign an identifier (in tis case l ) to that list? Like so:

filter((lambda x : len([z for z in l if z == x]) == 1), l@[1,1,2,3,4,4,5,6,6] )

I just used @ because in Haskell you can use @ in a similar way.

Is there some succinct syntax for this or do I need to break up the operation into several lines and assign l in a normal manner?

Answer 1

It is not possible to give a name 'on the fly' to the second parameter of filter .

If even it were, I think that Python code should be more explicit (see " The Zen of Python ") and I suggest to split the code in two or more lines.