如何寫出優雅的Python

標籤：

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 依次處理，zip是全部讀入後處理，如果在中間中斷的話，izip不需要讀入所有內容）

from itertools import izipnames = [‘raymond‘,‘rachel‘,‘mattew‘]colors = [‘red‘,‘green‘,‘blue‘,‘yellow‘]for name,color in izip(names,colors):    print name,‘-->‘,color

 

如何寫出優雅的Python