Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56) 
[GCC 4.4.3] on linux2
Type "copyright", "credits" or "license()" for more information.

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IDLE 2.6.5      
>>> a = ["spam","fruit","genes","mark"]
>>> "\t".join(a)
'spam\tfruit\tgenes\tmark'
>>> "".join(a)
'spamfruitgenesmark'
>>> "\n".join(a)
'spam\nfruit\ngenes\nmark'
>>> print "\n".join(a)
spam
fruit
genes
mark
>>> print "--hi--".join(a)
spam--hi--fruit--hi--genes--hi--mark
>>> b = set(("hi","blue","green","blue"))
>>> b
set(['blue', 'hi', 'green'])
>>> "\t".join(b)
'blue\thi\tgreen'
>>> c = [i for i in b]
>>> c
['blue', 'hi', 'green']
>>> c.sort()
>>> c
['blue', 'green', 'hi']
>>> d = {"A":"T","T":"A","G":"C","C":"G"}
>>> d
{'A': 'T', 'C': 'G', 'T': 'A', 'G': 'C'}
>>> d["G"]
'C'
>>> d["spam"]

Traceback (most recent call last):
  File "<pyshell#16>", line 1, in <module>
    d["spam"]
KeyError: 'spam'
>>> d["N"] = "N"
>>> d
{'A': 'T', 'C': 'G', 'T': 'A', 'G': 'C', 'N': 'N'}
>>> seq = "GATACA"
>>> s = "hi"
>>> s += " there"
>>> s
'hi there'
>>> for i in seq:
	print s[i]

	

Traceback (most recent call last):
  File "<pyshell#25>", line 2, in <module>
    print s[i]
TypeError: string indices must be integers, not str
>>> for i in range(len(seq)):
	print s[i]

	
h
i
 
t
h
e
>>> for i in seq:
	print seq[i]

	

Traceback (most recent call last):
  File "<pyshell#30>", line 2, in <module>
    print seq[i]
TypeError: string indices must be integers, not str
>>> for i in range(len(seq))):
	print seq[i]
	
SyntaxError: invalid syntax
>>> for i in range(len(seq)):
	print seq[i]

	
G
A
T
A
C
A
>>> for i in range(len(seq)):
	print d[seq[i]]

	
C
T
A
T
G
T
>>> compliment = ""
>>> for i in range(len(seq)):
	compliment += d[seq[i]]

	
>>> compliment
'CTATGT'
>>> compliment = ""
>>> for i in range(len(seq)):
	compliment = d[seq[i]] + compliment

	
>>> compliment
'TGTATC'
>>> help("".insert)

Traceback (most recent call last):
  File "<pyshell#45>", line 1, in <module>
    help("".insert)
AttributeError: 'str' object has no attribute 'insert'
>>> bases = []
>>> for i in range(len(seq)):
	bases.append(d[seq[i]])

	
>>> bases
['C', 'T', 'A', 'T', 'G', 'T']
>>> "".join(base)

Traceback (most recent call last):
  File "<pyshell#51>", line 1, in <module>
    "".join(base)
NameError: name 'base' is not defined
>>> "".join(bases)
'CTATGT'
>>> compliment = ""
>>> for i in seq:
	compliment = d[i] + compliment

	
>>> compliment
'TGTATC'
>>> for i in d.keys():
	print i

	
A
C
T
G
N
>>> import re
>>> r=re.compile("ATG")
>>> s = "CATATGCAT"
>>> p = r.search(s)
>>> r=re.compile("(ATG)")
>>> p = r.search(s)
>>> p.group(1)
'ATG'
>>> p.span()
(3, 6)
>>> r=re.compile("(A[TC]G)")
>>> s = "CATACGCAT"
>>> p = r.search(s)
>>> p.group(1)
'ACG'
>>> codon_re = re.compile("(.{3})")
>>> p = codon_re.search(s)
>>> p.group(1)
'CAT'
>>> for i in codon_re.finditer(s):
	print i.group(1)

	
CAT
ACG
CAT
>>>