Tips

1.%r 和%s
%r在print '%r' %("中文时")会输出一些non-ASCII characters；而%s就还会直接输出中文.
2.输入
raw_input()
3.python编程规范推荐

a = [1,2,3,4]
for i, item in enumerate(a):
    print i, item
# 打印
# 0 3
# 1 4
# 2 5

4.pyMongo中的
cursor.find(sort=[('filed_name','sort_type')])需要动态改变

5.python的json.dumps()和json.dump()的区别

1.dumps是将dict转换成str格式，loads是将str转换成dict格式。

import  json

a = {'name':'JSDu','age':22}

b = json.dumps(a)

print b, type(b)
{"age":22,"name":"JSDu"}<type 'str'>

json.loads(b)
{u'age':22,u'name':u'JSDu'}

print type(json.loads(b))
<tyoe 'dict'>

2.接着看dump和dumps的区别

import json

a = {'name':'JSDu','age':22}

b = json.dumps(a)

print b, type(b)
{"age":22,"name":"JSDu"}<type 'str'>

c = json.dump(a)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-5-92dc0d929363> in <module>()
----> 1 c = json.dump(a)
 
TypeError: dump() takes at least 2 arguments (1 given)

通过iPython的help（)函数查询json.dump

import json

a = {'name':'JSDu'}

fp = file('tesr.txt', 'w')

type(fp)
file

json.dump(a,fp)

fp.close()

cat test.txt
{'name':'JSDu'}