gistfile1.txt

# Three ways to do for loops:

## The common way

Most of the time, you have an iterable (a list, dictionary, string, etc) and want to loop over it.
Python makes this the easiest way to use a for loop:

``` python
contestants = ["First place finisher", "Second is still good", "the first civilized age"]
for contestant in contestants:
    print(contestant)
```

## Sometimes you want to add flair

Sometimes you write a list and you actually need the list index for some reason.  Instead of actually retrieving
the index you should indirectly get an equivalent to the index using enumerate.
``` python
medals = ["Gold", "Silver", "Bronze"]
contestants = ["First place finisher", "Second is still good", "the first civilized age"]

for idx, contestant in enumerate(contestants):
    print("{}: {}".format(medals[idx], contestant))
```

Although, if you control your input, there's usually one or more better ways:
``` python
medals = ["Gold", "Silver", "Bronze"]
contestants = ["First place finisher", "Second is still good", "the first civilized age"]

for medal, contestant in zip(medals, contestants):
    print("{}: {}".format(medal, contestant))
```

or
``` python
finisher = {1: ("Gold", "First place finisher"),
            2: ("Silver", "Second is still good"),
            3: ("Bronze", "the first civilized age")}
for _idx, (medal, contestant) in sorted(finisher.items()):
    # finisher.items() returns tuples of (key, value).  Since the value is itself a tuple,
    # each tuple looks like this: (1, ("Gold", "First place finisher"))
    #
    # sorted sorts those tuples.  Since the first entry in every tuple is a unique integer,
    # the tuples are returned in the order from 1 to 3.
    #
    # _idx, (medal, contestant) unpacks the returned tuples into their own variables. For the first entry,
    # _idx = 1, medal = "Gold", and contestnat = "First place finisher".
    # We don't have to do this unpacking if we don't want to the first time through this loop:
    # for _idx, value in sorted(finisher.items())  _idx = 1, value = ("Gold", "First place finisher")
    # Or even: 
    # for entry in sorted(finisher.items())   entry = (1, ("Gold", "First place finisher"))
    print("{}: {}".format(medal, contestant))
```

## On rare occassions, you want a counting loop

Sometimes you really do want to count a discrete range of numbers.  For those you should
iterate over the iterator returned by the range() function.  For instance to try something
three times and then give up:

``` python
for count in range(0, 3):
    try:
        data = http_get("http://flakey.resource.com/")
    except:
        # Try again
        pass
```

Or to print out the numbers from one to three.
``` python

# Print out a blank top 3 finishers' form
for place in range(1, 4):
    print("{}. ________________".format(place))
```