学习前准备,了解
基础环境部署,工作原理,发展和历史
pycharm,notepad++等工具
交互模式 命令行模式
废话不多说,直接上分
第一个脚本 打印
linux命令行下,vim 1.py
#!/bin/env python
print "hello world"
保存退出。
chmoc +x 1.py
python 1.py
[root@localhost xiaoai]# python 1.py
hello world
2.打印+运算
[root@localhost xiaoai]# cat 2.py
#!/bin/env python
print "The answer is",2*2
print "test"
print ("The answer is",2*2)
print "test"
print ("The answer is 2*2")
输出结果
[root@localhost xiaoai]# python 2.py
The answer is 4
test
('The answer is', 4)
test
The answer is 2*2
不知道为什么有时候会有括号,版本问题吗!?
3.对一个错误的python
[root@localhost xiaoai]# python 3.py
File "3.py", line 3
print(x,end=" ") # Appends a space instead of a newline
^
SyntaxError: invalid syntax
[root@localhost xiaoai]# cat 3.py
#!/bin/env python
print x,# Trailing comma suppresses newline
print(x,end=" ") # Appends a space instead of a newline
print (x,end="") # Appends a space instead of a newline
[root@localhost xiaoai]#
4.输入 输出
5.定义变量 交互式
[root@localhost xiaoai]# cat 5.py
#!/bash/env python
name=input('please enter your name:')
print ('hello~',name)
[root@localhost xiaoai]# python 5.py
please enter your name:qingqing
Traceback (most recent call last):
File "5.py", line 2, in
name=input('please enter your name:')
File "", line 1, in
NameError: name 'qingqing' is not defined
报错,因为没有加引号,很脑残
[root@localhost xiaoai]# python 5.py
please enter your name:'qingqing'
('hello~', 'qingqing')
[root@localhost xiaoai]#
6.约定俗成的4空格缩进
[root@localhost xiaoai]# cat 6.py
# print absolute value of an integer:
a = -78
if a >= 0:
print(a)
else:
print(-a)
[root@localhost xiaoai]# python 6.py
78
7.\转义与浮点数
[root@localhost xiaoai]# cat 7.py
#!/bash/env python
print ('I\'m ok')
print ('I\'m \"OK\"!')
print ('I\'m learning\nPython.')
print ('\\\n\\')
print (1.23e-3)
print 12.23e4
[root@localhost xiaoai]# python 7.py
I'm ok
I'm "OK"!
I'm learning
Python.
\
\
0.00123
122300.0
8.添加中午注释,报错
[root@localhost xiaoai]# cat 8.py
# -*- coding: utf-8 -*-
#!/bash/env python
#如果字符串里面有很多字符都需要转义,就需要加很多\,为了简化,Python还允许用r''表示''内部的字符串默认不转义,可以自己试试:
print ('\\\t\\\')
[root@localhost xiaoai]# python 8.py
File "8.py", line 4
print ('\\\t\\\')
^
SyntaxError: EOL while scanning string literal
[root@localhost xiaoai]#
网上给的方法就是在解释器第一行指定UTF-8.例如
# -*- coding: UTF-8-*-或者 #coding=utf-8
实际不管用
呵呵。
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本文来自企鹅号 - 还是遇上了你媒体
如有侵权,请联系 cloudcommunity@tencent.com 删除。