On 8/1/07, beginner <[EMAIL PROTECTED]> wrote: > Hi, > > Does anyone know how to put an assertion in list comprehension? I have > the following list comprehension, but I want to use an assertion to > check the contents of rec_stdl. I ended up using another loop which > essentially duplicates the functions of list comprehension. It just > look like a waste of coding and computer time to me. > > I just wish I could put the assertions into list comprehensions. > > x=[(rec_stdl[0].st/10000.0, > rec_stdl[0].cl, > rec_stdl[0].bb, > rec_stdl[0].bo, > rec_stdl[1].bb, > rec_stdl[1].bo, > rec_stdl[0].ex > ) > for rec_stdl in rec_by_ex if len(rec_stdl)==2 > ] > > #duplicated loop > if __debug__: > for rec_stdl in rec_by_ex: > l=len(rec_stdl) > assert(l<=2 and l>0) > if l==2: > assert(rec_stdl[0].c=="C" and rec_stdl[1].c=="P") > assert(rec_stdl[0].ex==rec_stdl[1].ex) > assert(rec_stdl[0].st==rec_stdl[1].st) > assert(rec_stdl[0].cp==rec_stdl[1].cp)
First: All your asserts are wrong. Assert is a statement, not a function. These specific ones will behave as expected, but it's easy to accidentally write ones that always pass this way. Secondly: This is a waste of code, because if __debug__ is not defined asserts will be skipped by the compiler. You could use the same loop block for both branches. Thirdly: This sort of testing is precisely what unit tests and/or doctests are for. -- http://mail.python.org/mailman/listinfo/python-list
