Python学习记录day2-变量类型、运算符

末蓝、 2022-07-14 00:52 232阅读 0赞

今天，跟着Alex喝了心灵的鸡汤：Be a new gentlmen

*  着装得体
 *  每天洗澡
 *  适当用香水
 *  女士优先
 *  不随地吐痰、不乱扔垃圾、不在人群中抽烟
 *  不大声喧哗
 *  不插队、碰到别人要说抱歉
 *  不在地铁上吃东西
 *  尊重别人的职业和劳动
 *  尊重别人隐私，不随便打听别人工资
 *  与人保持安全距离（1米）

*  多去旅行，一年至少一个国家
 *  多看书，电影，一年15本书，50+部电影
 *  学好英语
 *  保持不甘心、保持正能量
 *  做事件一定要学会换位思考，要想此事会不会给别人造成不好的困扰
 *  积极影响身边的人

**推荐读书**

*  《三体》
 *  《百年孤独》

**常量**：用全部大写字母命名变量名

**引入模块：**

import os  #推荐一行一个

**安装模块：**

pip install pandas

**os模块执行系统命令：**

os.system("df")
    os.popen("ifconfig").read()

**.pyc是什么？**

Python是一门基于虚拟机的语言，pyc 是由py文件经过编译后二进制文件，py文件变成pyc文件后，加载的速度有所提高，而且pyc是一种跨平台的字节码，是由python 的虚 拟机来执行的。

**数据类型**

1.数字

int（整型）

32位系统：-2\*\*31-1~2\*\*31-1

64位系统：-2\*\*63-1~2\*\*63-1

type()函数用于输出数据类型

long（长整型）

float（浮点型）

2.布尔值

真或假

1或0

3.字符串

推荐使用格式化输出：

Y = "test"
    str  = "This is a %s" %Y
    print (str)

PS：字符串是%s；整数是%d；浮点数是%f

\+号拼接字符串，效率低，因为其使用了多块内存空间。

**字符串**

字符串常用功能

*  移除空白
 *  分割
 *  索引
 *  切片
 *  长度

字符串操作

**删除空格**

>>> name="abc  "
    >>> name=name.strip()
    >>> name
    'abc'

**分割字符串**

>>> user="jim|jack"
    >>> print(user.split("|"))
    ['jim', 'jack']

**判断是否有空格**

>>> name="jim jack"
    >>> print(' ' in name)
    True

**首字母大写**

>>> print(name.capitalize())
    Jim jack

**格式化输出字符串**

>>> msg = "Hello, {name}, I am fine"
    >>> msg.format(name="Jimme")
    'Hello, Jimme, I am fine'
    >>> msg2="hahaha{0}, dddd{1}"
    >>> print(msg2.format('Ini',33))
    hahahaIni, dddd33

**切片**

>>> name="This is a test1,and what's your name"
    >>> print(name[2:7])
    is is

**查找**

>>> print(name.find('test'))
    10
    >>> print(name.find('tTTTT'))
    -1

**按长度填充字符串**

>>> print(name.center(40,'x')
    ... )
    xxThis is a test1,and what's your namexx

**字符串是否为数字**

>>> age="27"
    >>> print(age.isdigit())
    True

**字符串是否包含数字、开头、结局是否包含字符**

>>> name = "test01"
    >>> print(name.isalnum())
    True
    >>> print(name.endswith("df"))
    False
    >>> print(name.startswith("df"))
    False

**字符串大小写转换**

>>> print(name.upper(),name.lower())
    TEST01 test01

**列表**

列表基本操作：

*  索引
 *  切片
 *  追加
 *  删除
 *  长度
 *  切片
 *  循环
 *  包含

切片:取多个元素

>>> name = ["abc","jack",1,2,3,4]
    >>> name[-3:-1]
    [2, 3]
    >>> name[-3:0]
    []
    >>> name[-3:]
    [2, 3, 4]
    >>> name[:1]
    ['abc']
    >>> name[:2]
    ['abc', 'jack']

**切片后再切片**

>>> name[:2][:1][0]
    'abc'
    >>> name[:2][:1][0][1]
    'b'

**修改列表元素**

>>> name[3]="xiaoming"
    >>> name
    ['abc', 'jack', 1, 'xiaoming', 3, 4]

**插入**

>>> name.insert(2,"wangou")
    >>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 3, 4]

**追加**

>>> name.append("mac")
    >>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 3, 4, 'mac']

**删除**

>>> name.remove(3)
    >>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 4, 'mac']

**删除是只删除一个**

>>> name.append("mac")
    >>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 4, 'mac', 'mac']
    >> name.remove("mac")
    >>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 4, 'mac']
    >>> print(name[::2])
    ['abc', 'wangou', 'xiaoming', 'mac']

**元素是否在列表中，查找元素个数，查找元素位置**

>>> name
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 4, 'mac']
    >>> print(1 in name)
    True
    >>> print(name.count(4))
    1
    >>> print(name.index(4))
    5

**扩展（合并列表）**

>>> name2=["zhangzi","lizi","wangba"]
    >>> name.extend(name2)
    >>> print(name)
    ['abc', 'jack', 'wangou', 1, 'xiaoming', 4, 'mac', 'zhangzi', 'lizi', 'wangba']

**反序排列元素**

>>> name.reverse()
    >>> print(name)
    ['wangba', 'lizi', 'zhangzi', 'mac', 4, 'xiaoming', 1, 'wangou', 'jack', 'abc']

**元素排序（版本3不支持字符与数字排序）**

>>> name.sort()
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
 TypeError: unorderable types: int() < str()
 >>> name
 ['lizi', 'mac', 'wangba', 'zhangzi', 4, 'xiaoming', 1, 'wangou', 'jack', 'abc']
 >>> name=[1,3,2,4]
 >>> name.sort()
 >>> print(name)
 [1, 2, 3, 4]

**移除元素（默认移除最后一个元素）**

>>> name.pop()
    4
    >>> print(name)
    [1, 2, 3]

**移除指定元素**

>>> name.pop(1)
    2
    >>> print(name)
    [1, 3]

**拷贝**

>>> name3 = name.copy()
    >>> print(name3)
    [1, 3]

**拷贝时，第一层的元素（非列表）不会改变，元素为列表时与变量赋值一样，内存地址不变，所以2个列表内，元素为列表内的元素变化时，2个列表也一起改变**

>>> name=[1,2,3,[1,2,3,4],4]
    >>> name2 = name.copy()
    >>> name2
    [1, 2, 3, [1, 2, 3, 4], 4]
    >>> name[3][2]="TTT"
    >>> name
    [1, 2, 3, [1, 2, 'TTT', 4], 4]
    >>> name2
    [1, 2, 3, [1, 2, 'TTT', 4], 4]
    >>> name[2]="AAA"
    >>> name
    [1, 2, 'AAA', [1, 2, 'TTT', 4], 4]
    >>> name2
    [1, 2, 3, [1, 2, 'TTT', 4], 4]

**删除列表**

>>> del name2
 >>> name2
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
 NameError: name 'name2' is not defined

**元组**：不能被修改

基本操作：

*  索引
 *  切片
 *  循环
 *  长度
 *  包含

>>> r=(1,2,3,4,5)
 >>> r
 (1, 2, 3, 4, 5)
 >>> type(r)
 <class 'tuple'>
 >>> r[2]=1
 Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
 TypeError: 'tuple' object does not support item assignment

数据运算符

和其它语言一样，python也支持进行各种各样的数学和逻辑运算，我们一起来看一些。

python语言支持以下几种运算

算术运算

比较运算

Assignment Operators

二进制运算

关系运算

验证运算

算术运算

<table> 
 <tbody> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 运算符 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 描述 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 示例 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> + </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 加法运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a + b 得 30 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> - </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 减法运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a - b 得 -10 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> * </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 乘法运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a * b 得 200 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> / </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 除法运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> b / a 得 2 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> % </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 取模 - 将%号左边的值除以%号右边的值并且将得到的结果的余数返回 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 10%5得0 ，10%3 得1， 20%7 得6 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> ** </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 幂 - 返回x的y次幂，就是返回多少次方 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 2**8 得256 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> // </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 取整除 - 返回x除以y的商的整数部分 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 9//2得4 ， 9.0//2.0得4.0 </td> 
 </tr> 
 </tbody> 
</table>

比较运算

<table style="height:302px"> 
 <tbody> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 运算符 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 描述 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 示例 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> == </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 判断两个对象是否相等 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a == b) is not true. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> != </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 判断两个对象是否不相等 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a != b) is true. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &lt;&gt;&nbsp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 判断两个对象是否不相等 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &lt;&gt; b) is true. 与 != 运算符一样. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &gt;&nbsp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 大于 - 返回a是否大于b </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &gt; b) is not true. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &lt;&nbsp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 小于 - 返回a是否小于b </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &lt; b) is true. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &gt;= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 大于等于 - 返回a 是否大于等于b </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &gt;= b) is not true. </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &lt;= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 小于等于 - 返回a 是否小于等于b </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &lt;= b) is true. </td> 
 </tr> 
 </tbody> 
</table>

赋值运算

<table style="height:594px"> 
 <tbody> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 运算符 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 描述 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 示例 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> = </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 赋值 - 将右边的值赋值给左边的变量名 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c = a + b 将会把a+b的结果赋值给c </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> += </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自加赋值 - 将+=号左边的值与+=号右边的值相加，然后再把结果赋值给+=号左右的值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c += a相当于 c = c + a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> -= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自减赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c -= a相当于 c = c - a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> *= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自乘赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c *= a 相当于 c = c * a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> /= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自除赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c /= a 相当于 c = c / a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> %= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自取模赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c %= a 相当于 c = c % a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> **= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自求幂赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c **= a 相当于 c = c ** a </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> //= </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 自取整赋值 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> c //= a 相当于 c = c // a </td> 
 </tr> 
 </tbody> 
</table>

按位运算(二进制运算)

2个10进制数字的位运算

<table> 
 <tbody> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 运算符 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 描述 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 示例 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &amp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 与运算，这个二进制位必须在2组数中都为真，结果才返回真 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a &amp; b)得12，二进制位： 0000 1100 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> | </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 或运算，这个二进制位只需在其中一组数据中为真即返回真 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a | b)得 61，二进制位： 0011 1101 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> ^ </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 异或运算，只要这个二进制位在两组数据中不相同就返回真 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> (a ^ b)得 49 ，二进制位： 0011 0001 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &lt;&lt;&nbsp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 左移运算，将a整体向左移2位 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a &lt;&lt; 2得240，二进制位： 1111 0000 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &gt;&gt;&nbsp; </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 右移运算，将a整体向左移3位 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a &gt;&gt; 3得 7 ，二进制位： 0000 0111 </td> 
 </tr> 
 </tbody> 
</table>

看下面的运算过程：

<table> 
 <tbody> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 二进制位 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 8 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 7 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 6 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 5 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 4 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 3 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 2 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 结果 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 每位所代表的数字 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 128 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 64 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 32 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 16 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 8 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 4 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 2 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 60 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 13 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &nbsp;</td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> &amp;与运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 12 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> |或运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 61 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> ^异或运算 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 49 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a&lt;&lt;2 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 240 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> a&gt;&gt;3 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 0 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 1 </td> 
 <td style="margin:0px; padding:3px; border-color:#C0C0C0; border-collapse:collapse"> 7 </td> 
 </tr> 
 </tbody> 
</table>

逻辑运算符 and 、or 、not

关系运算符 in 、not in

验证运算符 is 、 is not

**字典**

id_db = {
        42342323232: {
            'name': "Yangkun",
            'age': 23,
            'addr': 'Dongbei'
        },
        23232424224: {
            'name': 'Guojin',
            'age': 22,
            'addr': 'Hubei'
        }
    }

字典的特性：

*  dict是无序的
 *  key必须是唯一的,so 天生去重

**增加**

>>> id_db[322323232332]={
    ...     'name':'Guojia',
    ...     'age':45,
    ...     'addr':'Changan'
    ... }
    >>>
    >>> print(id_db)
    {42342323232: {'addr': 'Dongbei', 'age': 23, 'name': 'Yangkun'}, 23232424224: {'addr': 'Hubei', 'age': 22, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}}

**修改**

>>> id_db[23232424224]['age']=32
    >>> print(id_db)
    {42342323232: {'addr': 'Dongbei', 'age': 23, 'name': 'Yangkun'}, 23232424224: {'addr': 'Hubei', 'age': 32, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}}

**删除**

>>> id_db[23232424224].pop("addr")
    'Hubei'
    >>> print(id_db)
    {42342323232: {'addr': 'Dongbei', 'age': 23, 'name': 'Yangkun'}, 23232424224: {'age': 32, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}}

**返回指定键的值，如果值不在字典中返回默认值**

>>> tmp = id_db.get(23232424224)
    >>> print(tmp)
    {'age': 32, 'name': 'Guojin'}

**更新**

>>> dic2 = {
    ...     42342323232: {
    ...         'name': "Yangkun",
    ...         'age': 23,
    ...         'addr': 'Shangdong'
    ...     }
    ... }
    >>> id_db.update(dic2)
    >>> print(id_db)
    {42342323232: {'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'}, 23232424224: {'age': 32, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}}

**返回元组对的列表**

>>> print(id_db.items())
    dict_items([(42342323232, {'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'}), (23232424224, {'age': 32, 'name': 'Guojin'}), (322323232332, {'addr': 'Changan', 'age': 45, 'name': 'Guojia'})])

**以列表返回字典中的所有值**

>>> print(id_db.values())
    dict_values([{'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'}, {'age': 32, 'name': 'Guojin'}, {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}])

**以列表返回一个字典所有的键**

>>> print(id_db.keys())
    dict_keys([42342323232, 23232424224, 322323232332])

**key是否存在于字典中**

>>> 42342323232 in id_db
    True

**get()方法类似, 如果键不已经存在于字典中，将会添加键并将值设为默认值**

>>> id_db.setdefault(42342323232)
    {'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'}
    >>> print(id_db)
    {42342323232: {'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'}, 23232424224: {'age': 32, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}, 4: None}

**用于创建一个新字典，以序列seq中元素做字典的键，value为字典所有键对应的初始值**

>>> print(dict.fromkeys([1,2,3,4,33,32],"TTTTEST"))
    {32: 'TTTTEST', 1: 'TTTTEST', 2: 'TTTTEST', 3: 'TTTTEST', 4: 'TTTTEST', 33: 'TTTTEST'}

**随机删除一个元素**

>>> print(id_db.popitem())
    (42342323232, {'addr': 'Shangdong', 'age': 23, 'name': 'Yangkun'})
    >>> print(id_db)
    {23232424224: {'age': 32, 'name': 'Guojin'}, 322323232332: {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}, 4: None}

**循环字典（效率低，因为有一个dict to list的转换过程）**

>>> for k,v in id_db.items():
    ...     print(k,v)
    ...
    23232424224 {'age': 32, 'name': 'Guojin'}
    322323232332 {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}
    4 None

>>> for key in id_db:   #效率高
    ...     print(key,id_db[key])
    ...
    23232424224 {'age': 32, 'name': 'Guojin'}
    322323232332 {'addr': 'Changan', 'age': 45, 'name': 'Guojia'}
    4 None

本文出自 “[ygqygq2][]” 博客，谢绝转载！

[ygqygq2]: http://ygqygq2.blog.51cto.com