python安装
python3:
1.拿到源码包(3.6) —>去官网下载()
2.tar zxf Python-3.6.4.tgz -C /opt/ #解压安装包
3.进入解压目录编译和安装：
yum install gcc zlib zlib-devel openssl-devel -y #解决依赖性
4.cd /opt/ cd Python-3.6.4/ #进入解压的安装包进行编译
./configure --prefix=/usr/local/python3 --with-ssl
–prefix：安装路径 --with-ssl：添加ssl加密
make && make install：安装
5.测试：cd /usr/local/python3/bin ./python3
6.添加python3的命令到环境变量中
方法1：
临时添加：
export PATH="/usr/local/python3/bin:$PATH"
python3
Python 3.6.4 (default, Aug 26 , 21:44:00)
[GCC 4.8.2 0120 (Red Hat 4.8.2-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
永久添加:
echo export PATH="/usr/local/python3/bin:$PATH" >> ~/.bashrc
vim ~/.bashrc
source ~/.bashrc
python3
Python 3.6.4 (default, Aug 26 , 21:44:00)
[GCC 4.8.2 0120 (Red Hat 4.8.2-16)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> quit
Use quit() or Ctrl-D (i.e. EOF) to exit
>>>
方法2：
做软连接
ln -s /usr/local/python3.6/bin/python3.6 /usr/local/bin/
##测试是否安装成功
python3
##安装ipython
cd /usr/local/python3.6/bin
pip3.6 install ipython
第一个py命令
#coding:utf-8
#python2.x:默认使用ASCII编码
#python3.x:默认使用UTF-8编码
#1.没有分号(编码规范 PEP8)
#2.严格按照缩进的语言
print('白茶清欢无别事')
print('越努力')
##注释
#单行注释
“”"
xxxxx 多行注释
xxxx
“”"
输入和输出
##python3.x
input():接收任意数据类型
python3.x中没有raw_input()
>>> input('Num:')
Num:2
'2'
>>> input('Num:')
Num:abc
'abc'
>>> input('Passwd:')
Passwd:123
'123'
#输入内容不回显
>>> import getpass
>>> num = getpass.getpass('请输入密码：')
请输入密码：
>>> print(num)
123
##python2.x
input():只支持正确的数值类型
raw_input():数值和字符串
>>> input('Num:')
Num:2
2
>>> input('Num:')
Num:1.2
1.2
>>> input('Num:')
Num:redhat
Traceback (most recent call last):
File "", line 1, in
File "", line 1, in
NameError: name 'redhat' is not defined
>>> raw_input('Num:')
Num:2
'2'
>>> raw_input('Num:')
Num:1,2
'1,2'
>>> raw_input('Num:')
Num:redhat
'redhat'
>>>
#如果接收到的数值要进行比较的时候，一定要转换为同一种类型
>>> age = input('age:')
age:19
>>> age
'19'
>>> age > 18
Traceback (most recent call last):
File "", line 1, in
TypeError: '>' not supported between instances of 'str' and 'int'
>>> age = int(age)
>>> age
19
>>> age > 18
True
>>> age = int(input('age:'))
age:18
>>> age
18
格式化输出
格式化输出
%s:代表字符串 %d:整型
>>> name = 'westos'
>>> name
'westos'
>>> age = 12
>>> print('%s的年龄是%d' %(name,age))
westos的年龄是12
>>> age = 18
>>> print('%s的年龄是%d' %(name,age))
westos的年龄是18
>>> age = '19'
>>> print('%s的年龄是%d' %(name,age))
Traceback (most recent call last):
File "", line 1, in
TypeError: %d format: a number is required, not str
>>> age = 19.5
>>> print('%s的年龄是%d' %(name,age))
westos的年龄是19
浮点型 %f
>>> money=23121312.32314432
>>> name = 'Tom'
>>> print('%s的工资为%f' %(name,money))
Tom的工资为23121312.323144
>>> money=60000
>>> print('%s的工资为%f' %(name,money))
Tom的工资为60000.000000
>>> money=60000.99
>>> print('%s的工资为%f' %(name,money))
Tom的工资为60000.990000
>>> print('%s的工资为%.2f' %(name,money))
Tom的工资为60000.99
>>> money=60000
>>> print('%s的工资为%.3f' %(name,money))
Tom的工资为60000.000
整数的占位：不够的位数 前面补0
>>> sid = 1
>>> name = 'lily'
>>> print('%s的学号为000%d' %(name,sid))
lily的学号为0001
>>> sid = 2
>>> print('%s的学号为000%d' %(name,sid))
lily的学号为0002
>>> sid = 10
>>> print('%s的学号为000%d' %(name,sid))
lily的学号为00010
>>> print('%s的学号为%.5d' %(name,sid))
lily的学号为00010
>>> sid = 1
>>> print('%s的学号为%.5d' %(name,sid))
lily的学号为00001
>>> sid = 20
>>> sid = 100
>>> print('%s的学号为%.5d' %(name,sid))
lily的学号为00100
百分号的实现
>>> scale = 0.1
>>> print('数据的比例是:%.2f' %(scale))
数据的比例是:0.10
>>> print('数据的比例是:%.2f' %(scale * 100))
数据的比例是:10.00
>>> print('数据的比例是:%.2f%' %(scale * 100))
Traceback (most recent call last):
File "", line 1, in
ValueError: incomplete format
>>> print('数据的比例是:%.2f%%' %(scale * 100))
数据的比例是:10.00%
变量
#驼峰命令法：
1.大驼峰：每一个单词的首字母都大写
FistName LastName
2.小驼峰：第一个单词小写开始后续单词首字母大写
fistName lastName
#str：表示一个字符串类型
name = '房东的喵'
print（name）
#int：表示一个整型
age = 22
print（age）
#float：表示一个浮点型
height = 178.5
print(height)
#bool:表示一个布尔型，只有True和False两个值
gender = True
print(gender)
#变量名只有在第一次出现的时候是定义变量
数据类型
整型
>>> a = 1
>>> print(a)
1
查看变量的类型
>>> type(a)
浮点型
>>> b = 1.2
>>> print(b)
1.2
>>> type(b)
>>> c = westos
Traceback (most recent call last):
File "", line 1, in
NameError: name 'westos' is not defined
字符串型
>>> c = 'westos'
>>> print(c)
westos
>>> c = "what's"
>>> print(c)
what's
>>> c = 'what's'
File "", line 1
c = 'what's'
^
SyntaxError: invalid syntax
>>> c = 'what\'s'
>>> print(c)
what's
bool型(只有两个值：True False 非0即真)
>>> a = 1
>>> bool(a)
True
>>> bool(0)
False
>>> bool('')
False
>>> bool(' ')
True
>>> bool('redhat')
True
数据类型之间的转换
>>> a = 1
>>> type(a)
>>> float(a)
1.0
>>> type(a)
>>> b = float(a)
>>> b
1.0
>>> b = 2.0
>>> int(b)
2
>>> c = 'redhat'
>>> int(c)
Traceback (most recent call last):
File "", line 1, in
ValueError: invalid literal for int() with base 10: 'redhat'
>>> b = 123
>>> str(b)
'123'
>>> c = '123'
>>> int(c)
123
>>> a
1
>>> b
123
>>> c
'123'
在内存中删除一个变量
>>> del a
>>> a
Traceback (most recent call last):
File "", line 1, in
NameError: name 'a' is not defined
>>> del b
>>> b
Traceback (most recent call last):
File "", line 1, in
NameError: name 'b' is not defined
算术运算符号
python2.x
>>> 5/2
2
>>> 100/300
0
>>> 5.0/2
2.5
>>> 100/300.0
0.3333333333333333
python2.x中除法需要将其中一个写为浮点型，不然回自己取整
python3.x
>>> 5/2
2.5
>>> 100/300
0.3333333333333333
>>>
取余
>>> 5%2
1
取整
>>> 5//2
2
>>> a = 1
>>> a = a+1
>>> a
2
>>> a += 1
>>> a
3
逻辑运算符
“”"
and
1 and 2
两个条件同时满足 就返回True
只要有一个条件不满足，就返回False
or
1 or 2
两个条件只要满足一个 就返回True
两个条件都不满足，就返回False
“”"
python_score = 60
c_score = 50
if python_score >= 60 and c_score >=60:
print('考试通过')
else:
print('考试不通过')
标签：name,python,age,数据类型,py3.6,Num,print,input,python3
来源： /luxunlx123/article/details/100228104
