[Tutor] Unexpected iterator
Hello, I am working my way through the tutorial, and I like trying variations, just to see what expected errors look like, and other ways things could be written. I tried a, b = 0, 0 and that worked. Then I tried this to (maybe) set both a and b to 0: >>> a, b = 0 Traceback (most recent call last): File "", line 1, in TypeError: 'int' object is not iterable I understand why it doesn't work, but I don't understand the wording of the exception. Could someone explain how I accidentally introduced iteration into the picture with my syntax? I have a feeling there's an interesting lesson hidden in this example... Thanks. -jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How to call a method with a print statement?
You are looking for the __str__ method. See http://docs.python.org/reference/datamodel.html#object.__str__ class Foo(): def __init__(self): pass def __str__(self) return "hello world!" -jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Unexpected Result in Test Sequence
When you declare list1 before "def p()" you are making it global. That means it will keep its values between invocations of p(). When you start function p, you don't reset list1 to empty. You divide each time by 1000, and but your list1 list is growing and growing and growing. That's why the total is growing, not giving the answer you were expecting. Either you need to reset list1 to empty each time p() starts, or (if you want to accumulate the results between calls to p()) you need to divide by the true number of items in the list, not by 1000. So replace /1000 with /len(list1). However, that brings me to something else interesting. You are doing an integer divide. That means you'll get integer results, which for your purposes are much less interesting than floating point ones. Replace the /1000 with /1000.0 and see what you get. (Move the declaration of list1 into p() also.) Another thing... play in the interpreter with range(1,5) and range(0,5). Can you see another little bug your program has? It is not doing precisely what you think it is yet... -jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Do you use unit testing?
> As a discipline - work out what we want to test, write the test, watch > it fail, make it pass - I find this a very productive way to think and > work. There's an emotional aspect too. Keeping a positive aspect keeps up flow, and seeing tests go from failing to passing feels really good. Making a change you're not completely confident in and seeing tests start failing immediately is also quite nice .. you immediately feel how close to correct the change in question is, and if it's worth fixing up or is leading you the wrong direction and should be reverted allowing you to take another stab at it. -jeff ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
