Python学习笔记-内置函数
Posted kingleoric
tags:
篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了Python学习笔记-内置函数相关的知识，希望对你有一定的参考价值。
json
SSAVL2470 10.90.24.81
将json编码的字符串转换为一个Python的数据结构
json_str = json.loads(doc)
如果将一个Python的数据结构转换为json编码的字符串用json.dumps(json_str)
如果你要处理的是文件而不是字符串，你可以使用 json.dump() 和 json.load() 来编码和解码JSON数据。例如：
# Writing JSON data
with open(‘data.json‘, ‘w‘) as f:
json.dump(data, f)
# Reading data back
with open(‘data.json‘, ‘r‘) as f:
data = json.load(f)
[[email protected] day]# cat check_codis2.py
#!/usr/bin/python
import json
class Student(object):
def __init__(self, name, age, score):
self.name = name
self.age = age
self.score = score
s = Student(‘Bob‘, 20, 88)
def student2dict(std):
return {
‘name‘: std.name,
‘age‘: std.age,
‘score‘: std.score
}
print(json.dumps(s, default=student2dict))
[[email protected] day]# python check_codis2.py
{"age": 20, "score": 88, "name": "Bob"}
存储需要监控的网页地址，并转换为字典：
[[email protected] day]# cat check_codis.py
#!/usr/bin/python
import urllib2
import json
response=urllib2.urlopen("http://10.130.11.211:8080/topom?forward=cep-codis-test")
doc = response.read()
json_str = json.loads(doc)
print json_str.keys()
print "compile is",json_str["compile"]
#print "stats is",json_str["stats"]
print "model is",json_str["model"]
print "version is",json_str["version"]
print "config is",json_str["config"]
[[email protected] day]# python check_codis.py
[u‘compile‘, u‘stats‘, u‘model‘, u‘version‘, u‘config‘]
compile is 2016-06-12 13:50:20 +0800 by go version go1.6.2 linux/amd64
model is {u‘start_time‘: u‘2016-06-22 16:51:56.982575937 +0800 CST‘, u‘pid‘: 4254, u‘sys‘: u‘Linux cep-elasearch-001.novalocal 2.6.32-504.1.3.el6.x86_64 #1 SMP Tue Nov 11 17:57:25 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux‘, u‘pwd‘: u‘/usr/local/go/src/github.com/CodisLabs/codis/bin‘, u‘admin_addr‘: u‘172.31.0.76:18080‘, u‘product_name‘: u‘cep-codis-test‘}
version is unknown version
config is {u‘coordinator_name‘: u‘zookeeper‘, u‘admin_addr‘: u‘0.0.0.0:18080‘, u‘coordinator_addr‘: u‘10.130.11.69:2181‘, u‘product_name‘: u‘cep-codis-test‘}
分解字典：
[[email protected] day]# cat check_codis6.py
#!/usr/bin/python
import urllib2
import json
response=urllib2.urlopen("http://10.130.11.211:8080/topom?forward=cep-codis-test")
doc = response.read()
json_str = json.loads(doc)
info = {}
info = json_str["stats"]
for k,v in info.items():
# print "key is %s,value is %s" %(k,v)
# print type(v)
if type(v) == dict:
for k1,v1 in v.items():
# print "key1 is %s,value1 is %s" %(k1,v1)
# print "value1 is %s" %(v1)
print type(v1)
print ‘end ‘
[[email protected] day]# python check_codis6.py
<type ‘bool‘>
<type ‘dict‘>
<type ‘int‘>
<type ‘int‘>
<type ‘list‘>
<type ‘dict‘>
<type ‘list‘>
<type ‘dict‘>
End
subprocess
In [4]: stdin,stdout=os.popen2(‘sort‘)
In [5]: stdin.write(‘hello‘)
In [6]: stdin.write(‘world‘)
In [7]: stdin.write(‘zhailiang\n‘)
In [8]: stdin.write(‘123\n‘)
In [9]: stdin.close()
In [11]: stdout.read()
Out[11]: ‘123\nhelloworldzhailiang\n‘
In [13]: from subprocess import Popen,PIPE
In [14]: p=Popen([‘ls‘],stdin=PIPE,stdout=PIPE,stderr=PIPE)
In [15]: p.stdout
Out[15]: <open file ‘<fdopen>‘, mode ‘rb‘ at 0x184bd20>
In [16]: p.stdout.read()
Out[16]: ‘1_zhailiang.txt\n2_walk.py\n2_walk_yield.py\n3_du.py\nanaconda-ks.cfg\ncheck_call.py\ninstall.log\ninstall.log.syslog\npip-1.4.1\npip-1.4.1.tar.gz\npip-tools-1.4.0.tar.gz\nsetuptools-2.0\nsetuptools-2.0.tar.gz\nzhailianghash2.py\nzhailianghash.py\n‘
P是子进程，print "main process"是父进程，p.wait()表示子进程执行完后再执行父进程，将当前结果输出到当前屏幕上
[[email protected] ~]# cat python 7_subprocess.py
cat: python: No such file or directory
#!/usr/bin/python
from subprocess import Popen,PIPE
#child
p=Popen([‘./test.sh‘],shell=True)
p.wait()
# farther
print "main process"
stdin, stdout, stderr分别表示程序的标准输入、输出、错误句柄。他们可以是PIPE，文件描述符或文件对象，也可以设置为None，表示从父进程继承。
Popen.stdin：如果在创建Popen对象是，参数stdin被设置为PIPE，Popen.stdin将返回一个文件对象用于策子进程发送指令。否则返回None。
Popen.stdout：如果在创建Popen对象是，参数stdout被设置为PIPE，Popen.stdout将返回一个文件对象用于策子进程发送指令。否则返回None。
Popen.stderr：如果在创建Popen对象是，参数stdout被设置为PIPE，Popen.stdout将返回一个文件对象用于策子进程发送指令。否则返回None。
默认父进程不等待新进程结束
[[email protected] ~]# python 7_subprocess.py
hello world
main process
以下该脚步相当于ls |grep py
[[email protected] ~]# cat 7_subprocess_1.py
#!/usr/bin/python
from subprocess import Popen,PIPE
p1=Popen([‘ls‘],stdout=PIPE)
p2=Popen([‘grep‘,‘py‘],stdin=p1.stdout,stdout=PIPE)
result=p2.stdout
for i in result:print i,
[[email protected] ~]# python 7_subprocess_1.py
2_walk.py
2_walk_yield.py
3_du.py
7_subprocess_1.py
7_subprocess.py
check_call.py
。。。。。。
Communicate
Python执行shell：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os
import platform
import subprocess
import commands
def subproc():
print "系统进程数："
subprocess.call("ps -ef|wc -l",shell=True)
def os_popen():
print "IP地址："
os1 = platform.system()
if os1 == "Linux":
print os1
ip1 =os.popen("/sbin/ifconfig eth0|grep ‘inet addr‘").read().strip().split(":")[1].split()[0]
print "\033[1;32;40m%s\033[0m" % ip1
def os_system():
os_command = ‘free -m‘
cls_node1 = "命令执行成功...."
cls_node2 = "命令执行失败...."
if os.system(os_command) == 0:
print "\n\033[1;32;40m%s\033[0m" % cls_node1
else:
print "\n\033[1;31;40m%s\033[0m" % cls_node2
def os_commands():
(status, output) = commands.getstatusoutput(‘pwd‘)
print status, output
def main():
subproc()
os_popen()
os_system()
os_commands()
if __name__ == "__main__":
main()
oracle中 python与SQL plus进行通信：
import os
from subprocess import Popen, PIPE
sqlplus = Popen(["sqlplus", "-S", "/", "as", "sysdba"], stdout=PIPE, stdin=PIPE)
sqlplus.stdin.write("select sysdate from dual;"+os.linesep)
sqlplus.stdin.write("select count(*) from all_objects;"+os.linesep)
out, err = sqlplus.communicate()
print out
This return output similar to:
SYSDATE
--------------
02-DEC-11
COUNT(*)
--------------
76147
还有个datetime的比较简单，就不记了
以上是关于Python学习笔记-内置函数的主要内容，如果未能解决你的问题，请参考以下文章