单行循环及多个变量迭代

例子：多条件迭代

for abc in ['The number is '+str(x)+'!!!!!' for x in range(5) if x %2==0]:

    print abc

结果：

The number is 0!!!!!
The number is 2!!!!!
The number is 4!!!!!

例子：字典迭代

dic= {'No1':'Janme','No2':'Lemon'}
for no, name in dic.iteritems():
    print no,'is ', name

结果：

No1 is  Janme
No2 is  Lemon

例子：字符串中的一部分进行迭代

['the number' + str(x) + 'is best!' for x in range(4)]

结果：

['the number0is best!', 'the number1is best!', 'the number2is best!', 'the number3is best!']

例子：把list中的所有元素大写改成小写

L = ['SAHPE','WHAT','SALT']
[s.lower() for s in L]

结果：

['sahpe', 'what', 'salt']

如果把[]换成()，则上面的列表将变成生成器，累死yield，这样占用内存更小。