Python slice

slice.py

# calculate the length of the n-gram
kwic = 'amongst them a black there was one'.split()
n = len(kwic)
print n
-> 7

# calculate the index position of the keyword
keyindex = n // 2
print keyindex
-> 3

# display the items before the keyword
print kwic[:keyindex]
-> ['amongst', 'them', 'a']

# display the keyword only
print kwic[keyindex]
-> black

# display the items after the keyword
print kwic[(keyindex+1):]
-> ['there', 'was', 'one']