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Looping over a range of numbers
Bad：
for i in [0,1,2,3,4,5]: print i**2
Good:
for i in range(6): print i**2
Looping over a collection:
Bad:
colors = [ ‘red‘,‘green‘,‘blue‘,‘yellow‘] for i in range(len(colors)): print colors[i]
Good:
for i in colors: print colors[i]
Looping backwards
Bad:
colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] for i in range(len(colors)-1,-1,-1): print colors(i)
Good:
colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] for color in reversed(colors): print color
Looping over a collection and indicies
Bad:
colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘]
for i in range(len(colors)):
print i, ‘-->‘, colors[i]
Good:
colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] for i,color in enmerate(colors): print i, ‘-->‘, colors[i]
Looping over two collections
Bad:
names = [‘raymond‘,‘rachel‘,‘mattew‘] colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] n = min(len(names),len(colors)) for i in range(n): print names[i],‘-->‘,colors[i]
Good:
names = [‘raymond‘,‘rachel‘,‘mattew‘] colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] for name,color in zip(names,colors): print name,‘-->‘,color
Even beeter.(izip 依次处理，zip是全部读入后处理，如果在中间中断的话，izip不需要读入所有内容）
from itertools import izip names = [‘raymond‘,‘rachel‘,‘mattew‘] colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘] for name,color in izip(names,colors): print name,‘-->‘,color
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原文地址：http://www.cnblogs.com/db2zos/p/4660007.html
