>>> strand = "cgcgcgaaattt"
>>> len(strand)
12
>>> [1 for ch in strand]
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
>>> xx = [1 for ch in strand]
>>> xx
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
>>> len(xx)
12
>>> sum(xx)
12
>>> yy = [0 for ch in strand]
>>> yy
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
>>> yy = [ch+ch for ch in strand
... ]
>>> yy
['cc', 'gg', 'cc', 'gg', 'cc', 'gg', 'aa', 'aa', 'aa', 'tt', 'tt', 'tt']
>>> strand
'cgcgcgaaattt'
>>> [3 for nutsy in strand]
[3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3]
>>> [nutsy*5 for nutsy in strand]
['ccccc', 'ggggg', 'ccccc', 'ggggg', 'ccccc', 'ggggg', 'aaaaa', 'aaaaa',
'aaaaa', 'ttttt', 'ttttt', 'ttttt']
>>> strand
'cgcgcgaaattt'
>>> [1 for ch in strand if ch == 'g' or ch = 'c']
  File "<console>", line 1
    [1 for ch in strand if ch == 'g' or ch = 'c']
                                           ^
SyntaxError: invalid syntax
>>> [1 for ch in strand if ch == 'g' or ch == 'c']
[1, 1, 1, 1, 1, 1]
>>> cgs = [1 for ch in strand if ch == 'g' or ch == 'c']
>>> cgs
[1, 1, 1, 1, 1, 1]
>>> len(cgs)
6
>>> sum(cgs)
6
>>> strand
'cgcgcgaaattt'
>>> words = ["zebra", "bear", "cow", "dog"]
>>> words
['zebra', 'bear', 'cow', 'dog']
>>> len(words)
4
>>> [w for w in words if len(w) > 4]
['zebra']
>>> [len(w) for w in words if len(w) == 3]
[3, 3]
>>> [w for w in words if len(w) == 3]
['cow', 'dog']
>>> [x for w in words if len(w) == 3]
Traceback (most recent call last):
  File "<console>", line 1, in <module>
NameError: name 'x' is not defined
>>> [x for x in words if len(x) == 3]
['cow', 'dog']
>>> ['x' for w in words if len(w) == 3]
['x', 'x']
>>> x = 7
>>> [x for w in words if len(w) == 3]
[7, 7]
>>> zoo =['zebra', 'antelope', 'bear', 'orangutan', 'unicorn', 'chimp',
'goldfish']
>>> zoo
['zebra', 'antelope', 'bear', 'orangutan', 'unicorn', 'chimp',
'goldfish']
>>> len(zoo)
7
>>> [len(w) for w in zoo]
[5, 8, 4, 9, 7, 5, 8]
>>> max([len(w) for w in zoo])
9
>>> zoo[9]
Traceback (most recent call last):
  File "<console>", line 1, in <module>
IndexError: list index out of range
>>> max([len(w) for w in zoo])
9
>>> [len(w) for w in zoo].index(9)
3
>>> zoo[3]
'orangutan'
>>> max(zoo)
'zebra'
>>> zoo
['zebra', 'antelope', 'bear', 'orangutan', 'unicorn', 'chimp',
'goldfish']
>>> min(zoo)
'antelope'
>>> zoo.append("aardvark")
>>> zoo
['zebra', 'antelope', 'bear', 'orangutan', 'unicorn', 'chimp',
'goldfish', 'aardvark']
>>> min(zoo)
'aardvark'
>>>