Lists and for loops:

51280:

initialize has_dups to False
for each item in the list, check if the number of times it is found in the
   list is > 1.  If so, set has_dups to True.
There is no else: part to this if clause.

51290:

initialize contains to True
Similar to 51280: only set contains to False in an if clause, with no else
  part.

51292:

create a list called triangulars
create a variable runningTotal, set to 0
Use a for loop, with a range from 1 to n+1.

51275:

initialize list3 to empty list.
Use an index-based for loop.

51276:

Very similar to 51275.  Just change the range() call.

51284:

Initialize the list.
Use a for loop with range().  Remember that range takes 3 values: start,
  stop, step.

51285:

Very similar to 51284.

51287:

Initialize the list to []
Create a variable, initialized to 1.
Use a while loop.
In the while loop, multiply the variable by ratio.

51210:

No hints on this one, except that it can be done with no "temporary"
  variables, and on one line.

51216:

Similar to 51210: there is a list method that solves this problem.

51219:

Can be done in one line.  There is a built-in function max().

51263:

Variable initialization, and then a for loop with an if inside it.

51295:

Initialize the result new_list
Loop over each element in lst1.
The loop contains an if statement.

51296:

Very similar 51295, but uses two (non-nested) for loops.


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Using Lists as Parameters

51163:

Recall that you can reverse a string by slicing it with step -1:
    a[::-1]  produces a string that is the reverse of a.

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Tuples and Mutability

No hints on any problems.

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Objects Revisited

No hints needed, I hope.

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User Defined Classes

*** NOTE *** NOTE *** NOTE ***

In these exercises, you'll have to write some class definitions.  Class
definitions involve multiple levels of indentation. Turings Craft has some
problems with spaces vs. tabs.  I have spoken to the authors of this
website and they have made improvements, but I've found things are still
not perfect...

If you have problems with some code, make *** sure *** that you use all
spaces to do your indentation.  Sometimes TC will insert tabs for you -- I
would erase those and type spaces instead.


*** NOTE *** NOTE *** NOTE ***

For all exercises:

These exercises often say something like this:

Write the definition of a clas Counter containing:
   o an instance variable counter of type int, initialized to 0.
   o etc.

One could write this, and it would theoretically be correct:

class Counter:
    counter = 0         # THIS LINE I DO NOT LIKE
    def __init__(self):
        ....

Writing code this way does work, but actually you are making a *class
variable* instead of an instance variable.  ** I DO NOT LIKE THIS. **

Instead, you should write:

class Counter:
    def __init__(self):
        self.counter = 0

This code creates the instance variable in the constructor, which is what
the book teaches you and what I prefer.