# tuples are like lists, but immutable
>>> l = [ 0, 1, 2 ]
>>> type(l)
Out[1]: list
>>> t = ( 0, 1, 2 )
>>> type(t)
Out[1]: tuple
>>> l[0] = 'a'
>>> l
Out[1]: ['a', 1, 2]
# trying to change a tuple causes an error
>>> t[0] = 'a'
Traceback (most recent call last):
  File "/Users/guestuser/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2721, in run_code
    exec code_obj in self.user_global_ns, self.user_ns
  File "<ipython-input-1-91a50260f243>", line 1, in <module>
    t[0] = 'a'
TypeError: 'tuple' object does not support item assignment


# typical template for iterating over a sequence using indexing
>>> for k in range(len(l)):
…    print(str(k) + "\t" + str(l[k])) 
0	a
1	1
2	2
# python function that bundles index and value as a tuple
>>> list(enumerate(l))
Out[1]: [(0, 'a'), (1, 1), (2, 2)]
>>> for (k,v) in enumerate(l):
...    print(str(k) + "\t" + str(v))
0	a
1	1
2	2
# python function that bundles multiple lists into one lists of tuples
>>> zip(l, t)
Out[1]: [('a', 0), (1, 1), (2, 2)]
>>> for (lv,tv) in zip(l, t):
…    print(str(lv) + "\t" + str(tv)) 
a	0
1	1
2	2


# fun with tuples --- swapping!
>>> a = 12
>>> b = 'z'
>>> print(str(a) + '\t' + str(b))
12	z
# swapping "manually"
>>> c = a
>>> a = b
>>> b = c
>>> print(str(a) + '\t' + str(b))
z	12
# swapping using tuples
>>> (b, a) = (a, b)
>>> print(str(a) + '\t' + str(b))
12	z


# representing "data" as a tuple
>>> color = (128, 255, 0)
# using index to get specific "field"
>>> color[0]
Out[1]: 128
>>> colorList = [ color, (0, 0, 0), (255, 255, 255) ]
>>> colorList[0]
Out[1]: (128, 255, 0)
>>> from collections import namedtuple
>>> Color = namedtuple('Color', 'red, green, blue')
>>> color = Color(128, 255, 0)
>>> print(color)
Color(red=128, green=255, blue=0)
# can use name to get data
>>> color.red
Out[1]: 128
# or can still use index if you want
>>> color[0]
Out[1]: 128