Python基础——第二章第一部分字符串方法转义及编码解码

1、字符串方法

1.1、查

（1）count：统计字符串中某元素出现的次数

>>>zf = 'hello world'
>>>zf.count('l')
3
>>>zf.count('o')
2

（2）index：查找元素所在的下标

>>>zf = 'hello world'
>>>zf.index('o')
4
>>>zf.index('l')
2
>>>zf.index('l',3)   '''这里是从下标为3的位置开始查找'''
3

（3）find：查找

>>>zf = 'hello world'
>>>zf.find('a')   '''字符串中若不存在要查找的元素，则返回-1'''
-1

（4）isdigit：判断字符串是否为纯数字，是返回True，否返回False

>>>'af4s5f4f6'.isdigit()
False
>>>'18544674'.isdigit()
True

（5）isalpha：判断字符串是否为纯字母，是返回True，否返回False

>>>'af4s5f4f6'.isalpha()
False
>>>'dbsjfbKL'.isdigit()
True

（6）isupper：判断字符串是否为纯大写字母，是返回True，否返回False

>>>'aGHJ4s5fHlsd6'.isupper()
False
>>>'HJJKJKIK'.issupper()
True>>>'aKHGs5f4f6'.upper()
'AKHGS5F4F6'

（7）islower：判断字符串是否为纯小写字母，是返回True，否返回False

>>>'aGHJ4s5fHlsd6'.islower()
False
>>>'fghsadfv'.islower()
True

1.2、改

（1）upper：将字符串中所有的小写字母改为大写字母

>>>'aKHGs5f4f6'.upper()
'AKHGS5F4F6'

（2）lower：将字符串中所有的大写字母改为小写字母

>>>'aKHGs5f4f6'.lower()
'akhgs5f4f6'

（3）capitalize：字符串第一个字母大写，若字符串第一个字符是数字的话，该方法无效

>>>'hello world '.capitalize()
'Hello world'
>>>'22hello world '.capitalize()
'22hello world'

（4）title：每一个单词首字母大写，字符串第一个字符是数字的话，也会将数字之后的第一个字母改写大写

>>>'hello world '.title()
'Hello World'
>>>'2hello 3world '.title()
'2Hello 3World'

1.3、删

（1）strip：删除字符串中所有的空格

>>>'    jhk   '.strip()
'jhk'
>>>'    jhk   '.lstrip()  '''lstrip是删除字符串左边的空格‘’‘’
'jhk   '
>>>'    jhk   '.lstrip()  '''rstrip是删除字符串右边的空格‘’‘’
'    jhk'

（2）split：分离字符串

>>>'a b c d'.split()  #如果没有指定分离位置，则默认以空格分离，并删除空格
['a','b','c','d']>>>a='hello world python'
>>>a.split('o')   #如果有指定分离字符，则按照指定字符分离，并删除该指定字符
['hell',' w','rld pyth','n']

（3）replace：替换字符串中的字符

>>>a='hello world python'
>>>a.replace('o','')  #将字符串中的字符替换为空格，相当于删除该字符
'hell wrld pythn'
>>>a.replace('o','xx')  #将字符串中的字符替换为指定的字符
'hellxx wxxrld pythxxn'
>>>a.replace('o','xx',1)  #将字符串中某一个字符替换为指定的字符
'hellxx world python' #这里仅hello的'o'被替换成'xx'
>>>a.replace('o','xx',2)  #这里的数字代表的是该方法杯执行几次
'hellxx wxxrld python' #这里仅hello、world的'o'被替换成'xx'，这里就执行了2次

1.4、增

字符串拼接

（1）+拼接

>>>'hello'+'wolrd'
'hello world'

（2）join拼接

>>>''.join(['hello',' wolrd'])
'hello world'
>>>''.join(('hello',' wolrd'))   #要拼接的字符串必须是一个整体，join才可以正确被执行，如果把小括号或者中括号去掉，则会报错
'hello world'

2、字符串的转义

当字符前面加上\，字符就不在表示字符本身的意思，表述ASCII码中不能显示字符

2.1、\n：换行

>>>li = 'aaaa\nbb'
>>>print(li)
aaaa
bb

2.2、\t：水平制表符

>>>li = 'aaaa\tbb'
>>>print(li)
aaaa       bb

2.3、\b：退格

2.4、\r：回车，当前位置移到本行开头

>>>li = 'aaaa\rbb'
>>>print(li)
bbaa

2.5、\：代表反斜杠\

>>>li = 'aaaa\\bb'
>>>print(li)
aaaa\bb

2.6、’：代表单引号

>>>li = 'aaaa\'bb'
>>>print(li)
aaaa'bb

2.7、\0：空格

>>>li = 'aaaa\0bb'
>>>print(li)
aaaa bb

2.8、\a系统提示符

>>>li = 'aaaa\abb'
>>>print(li)
aaaabb

2.9、去除字符串转移，在字符串前加上r即可

>>>print(r 'aaaa\\bb')  #字符串前加上r，这里会把所有字符打印出来，会多用于正则
r'aaaa\bb'

3、格式化输出

什么是格式化输出呢？
格式化输出就是我们想把数据按照特定要求的形式输出
下面我来介绍下%和format两种用法

3.1、%的用法

（1）字符串的格式化输出（%s）

>>>a = 'hello world'
>>>print('%s',a)
hello world

（2）整数型的格式化输出（%d）

>>>a = 26
>>>print('%d',a)
26

（3）浮点型小数的格式化输出（%f、%e）

>>>a = 1.23
>>>print('%f',a)   #保留小数点后6位
1.230000
>>>print('%.3f',a)   #保留小数点后3位
1.230>>>print('%e',a)   #保留小数点后6位，并以科学计数法表示
1.230000e+00
>>>print('%.3e',a)   #保留小数点后3位，并以科学计数法表示
1.230e+00

3.2、format的用法

（1）不带编号

>>>print('{},{},{}'.format([1,2,3],4,5)
'[1,2,3]45'

（2）带编号

>>>print('{2},{0[1]},{1}'.format([1,2,3],4,5)
'524'

4、字符串编码解码

#mermaid-svg-ubOeeBJklIywtYaj .label{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);fill:#333;color:#333}#mermaid-svg-ubOeeBJklIywtYaj .label text{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .node rect,#mermaid-svg-ubOeeBJklIywtYaj .node circle,#mermaid-svg-ubOeeBJklIywtYaj .node ellipse,#mermaid-svg-ubOeeBJklIywtYaj .node polygon,#mermaid-svg-ubOeeBJklIywtYaj .node path{fill:#ECECFF;stroke:#9370db;stroke-width:1px}#mermaid-svg-ubOeeBJklIywtYaj .node .label{text-align:center;fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .node.clickable{cursor:pointer}#mermaid-svg-ubOeeBJklIywtYaj .arrowheadPath{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .edgePath .path{stroke:#333;stroke-width:1.5px}#mermaid-svg-ubOeeBJklIywtYaj .flowchart-link{stroke:#333;fill:none}#mermaid-svg-ubOeeBJklIywtYaj .edgeLabel{background-color:#e8e8e8;text-align:center}#mermaid-svg-ubOeeBJklIywtYaj .edgeLabel rect{opacity:0.9}#mermaid-svg-ubOeeBJklIywtYaj .edgeLabel span{color:#333}#mermaid-svg-ubOeeBJklIywtYaj .cluster rect{fill:#ffffde;stroke:#aa3;stroke-width:1px}#mermaid-svg-ubOeeBJklIywtYaj .cluster text{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);font-size:12px;background:#ffffde;border:1px solid #aa3;border-radius:2px;pointer-events:none;z-index:100}#mermaid-svg-ubOeeBJklIywtYaj .actor{stroke:#ccf;fill:#ECECFF}#mermaid-svg-ubOeeBJklIywtYaj text.actor>tspan{fill:#000;stroke:none}#mermaid-svg-ubOeeBJklIywtYaj .actor-line{stroke:grey}#mermaid-svg-ubOeeBJklIywtYaj .messageLine0{stroke-width:1.5;stroke-dasharray:none;stroke:#333}#mermaid-svg-ubOeeBJklIywtYaj .messageLine1{stroke-width:1.5;stroke-dasharray:2, 2;stroke:#333}#mermaid-svg-ubOeeBJklIywtYaj #arrowhead path{fill:#333;stroke:#333}#mermaid-svg-ubOeeBJklIywtYaj .sequenceNumber{fill:#fff}#mermaid-svg-ubOeeBJklIywtYaj #sequencenumber{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj #crosshead path{fill:#333;stroke:#333}#mermaid-svg-ubOeeBJklIywtYaj .messageText{fill:#333;stroke:#333}#mermaid-svg-ubOeeBJklIywtYaj .labelBox{stroke:#ccf;fill:#ECECFF}#mermaid-svg-ubOeeBJklIywtYaj .labelText,#mermaid-svg-ubOeeBJklIywtYaj .labelText>tspan{fill:#000;stroke:none}#mermaid-svg-ubOeeBJklIywtYaj .loopText,#mermaid-svg-ubOeeBJklIywtYaj .loopText>tspan{fill:#000;stroke:none}#mermaid-svg-ubOeeBJklIywtYaj .loopLine{stroke-width:2px;stroke-dasharray:2, 2;stroke:#ccf;fill:#ccf}#mermaid-svg-ubOeeBJklIywtYaj .note{stroke:#aa3;fill:#fff5ad}#mermaid-svg-ubOeeBJklIywtYaj .noteText,#mermaid-svg-ubOeeBJklIywtYaj .noteText>tspan{fill:#000;stroke:none}#mermaid-svg-ubOeeBJklIywtYaj .activation0{fill:#f4f4f4;stroke:#666}#mermaid-svg-ubOeeBJklIywtYaj .activation1{fill:#f4f4f4;stroke:#666}#mermaid-svg-ubOeeBJklIywtYaj .activation2{fill:#f4f4f4;stroke:#666}#mermaid-svg-ubOeeBJklIywtYaj .mermaid-main-font{font-family:"trebuchet ms", verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .section{stroke:none;opacity:0.2}#mermaid-svg-ubOeeBJklIywtYaj .section0{fill:rgba(102,102,255,0.49)}#mermaid-svg-ubOeeBJklIywtYaj .section2{fill:#fff400}#mermaid-svg-ubOeeBJklIywtYaj .section1,#mermaid-svg-ubOeeBJklIywtYaj .section3{fill:#fff;opacity:0.2}#mermaid-svg-ubOeeBJklIywtYaj .sectionTitle0{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .sectionTitle1{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .sectionTitle2{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .sectionTitle3{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .sectionTitle{text-anchor:start;font-size:11px;text-height:14px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .grid .tick{stroke:#d3d3d3;opacity:0.8;shape-rendering:crispEdges}#mermaid-svg-ubOeeBJklIywtYaj .grid .tick text{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .grid path{stroke-width:0}#mermaid-svg-ubOeeBJklIywtYaj .today{fill:none;stroke:red;stroke-width:2px}#mermaid-svg-ubOeeBJklIywtYaj .task{stroke-width:2}#mermaid-svg-ubOeeBJklIywtYaj .taskText{text-anchor:middle;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .taskText:not([font-size]){font-size:11px}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutsideRight{fill:#000;text-anchor:start;font-size:11px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutsideLeft{fill:#000;text-anchor:end;font-size:11px}#mermaid-svg-ubOeeBJklIywtYaj .task.clickable{cursor:pointer}#mermaid-svg-ubOeeBJklIywtYaj .taskText.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutsideLeft.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutsideRight.clickable{cursor:pointer;fill:#003163 !important;font-weight:bold}#mermaid-svg-ubOeeBJklIywtYaj .taskText0,#mermaid-svg-ubOeeBJklIywtYaj .taskText1,#mermaid-svg-ubOeeBJklIywtYaj .taskText2,#mermaid-svg-ubOeeBJklIywtYaj .taskText3{fill:#fff}#mermaid-svg-ubOeeBJklIywtYaj .task0,#mermaid-svg-ubOeeBJklIywtYaj .task1,#mermaid-svg-ubOeeBJklIywtYaj .task2,#mermaid-svg-ubOeeBJklIywtYaj .task3{fill:#8a90dd;stroke:#534fbc}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutside0,#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutside2{fill:#000}#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutside1,#mermaid-svg-ubOeeBJklIywtYaj .taskTextOutside3{fill:#000}#mermaid-svg-ubOeeBJklIywtYaj .active0,#mermaid-svg-ubOeeBJklIywtYaj .active1,#mermaid-svg-ubOeeBJklIywtYaj .active2,#mermaid-svg-ubOeeBJklIywtYaj .active3{fill:#bfc7ff;stroke:#534fbc}#mermaid-svg-ubOeeBJklIywtYaj .activeText0,#mermaid-svg-ubOeeBJklIywtYaj .activeText1,#mermaid-svg-ubOeeBJklIywtYaj .activeText2,#mermaid-svg-ubOeeBJklIywtYaj .activeText3{fill:#000 !important}#mermaid-svg-ubOeeBJklIywtYaj .done0,#mermaid-svg-ubOeeBJklIywtYaj .done1,#mermaid-svg-ubOeeBJklIywtYaj .done2,#mermaid-svg-ubOeeBJklIywtYaj .done3{stroke:grey;fill:#d3d3d3;stroke-width:2}#mermaid-svg-ubOeeBJklIywtYaj .doneText0,#mermaid-svg-ubOeeBJklIywtYaj .doneText1,#mermaid-svg-ubOeeBJklIywtYaj .doneText2,#mermaid-svg-ubOeeBJklIywtYaj .doneText3{fill:#000 !important}#mermaid-svg-ubOeeBJklIywtYaj .crit0,#mermaid-svg-ubOeeBJklIywtYaj .crit1,#mermaid-svg-ubOeeBJklIywtYaj .crit2,#mermaid-svg-ubOeeBJklIywtYaj .crit3{stroke:#f88;fill:red;stroke-width:2}#mermaid-svg-ubOeeBJklIywtYaj .activeCrit0,#mermaid-svg-ubOeeBJklIywtYaj .activeCrit1,#mermaid-svg-ubOeeBJklIywtYaj .activeCrit2,#mermaid-svg-ubOeeBJklIywtYaj .activeCrit3{stroke:#f88;fill:#bfc7ff;stroke-width:2}#mermaid-svg-ubOeeBJklIywtYaj .doneCrit0,#mermaid-svg-ubOeeBJklIywtYaj .doneCrit1,#mermaid-svg-ubOeeBJklIywtYaj .doneCrit2,#mermaid-svg-ubOeeBJklIywtYaj .doneCrit3{stroke:#f88;fill:#d3d3d3;stroke-width:2;cursor:pointer;shape-rendering:crispEdges}#mermaid-svg-ubOeeBJklIywtYaj .milestone{transform:rotate(45deg) scale(0.8, 0.8)}#mermaid-svg-ubOeeBJklIywtYaj .milestoneText{font-style:italic}#mermaid-svg-ubOeeBJklIywtYaj .doneCritText0,#mermaid-svg-ubOeeBJklIywtYaj .doneCritText1,#mermaid-svg-ubOeeBJklIywtYaj .doneCritText2,#mermaid-svg-ubOeeBJklIywtYaj .doneCritText3{fill:#000 !important}#mermaid-svg-ubOeeBJklIywtYaj .activeCritText0,#mermaid-svg-ubOeeBJklIywtYaj .activeCritText1,#mermaid-svg-ubOeeBJklIywtYaj .activeCritText2,#mermaid-svg-ubOeeBJklIywtYaj .activeCritText3{fill:#000 !important}#mermaid-svg-ubOeeBJklIywtYaj .titleText{text-anchor:middle;font-size:18px;fill:#000;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj g.classGroup text{fill:#9370db;stroke:none;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family);font-size:10px}#mermaid-svg-ubOeeBJklIywtYaj g.classGroup text .title{font-weight:bolder}#mermaid-svg-ubOeeBJklIywtYaj g.clickable{cursor:pointer}#mermaid-svg-ubOeeBJklIywtYaj g.classGroup rect{fill:#ECECFF;stroke:#9370db}#mermaid-svg-ubOeeBJklIywtYaj g.classGroup line{stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj .classLabel .box{stroke:none;stroke-width:0;fill:#ECECFF;opacity:0.5}#mermaid-svg-ubOeeBJklIywtYaj .classLabel .label{fill:#9370db;font-size:10px}#mermaid-svg-ubOeeBJklIywtYaj .relation{stroke:#9370db;stroke-width:1;fill:none}#mermaid-svg-ubOeeBJklIywtYaj .dashed-line{stroke-dasharray:3}#mermaid-svg-ubOeeBJklIywtYaj #compositionStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #compositionEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #aggregationStart{fill:#ECECFF;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #aggregationEnd{fill:#ECECFF;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #dependencyStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #dependencyEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #extensionStart{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj #extensionEnd{fill:#9370db;stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj .commit-id,#mermaid-svg-ubOeeBJklIywtYaj .commit-msg,#mermaid-svg-ubOeeBJklIywtYaj .branch-label{fill:lightgrey;color:lightgrey;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .pieTitleText{text-anchor:middle;font-size:25px;fill:#000;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .slice{font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj g.stateGroup text{fill:#9370db;stroke:none;font-size:10px;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj g.stateGroup text{fill:#9370db;fill:#333;stroke:none;font-size:10px}#mermaid-svg-ubOeeBJklIywtYaj g.statediagram-cluster .cluster-label text{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj g.stateGroup .state-title{font-weight:bolder;fill:#000}#mermaid-svg-ubOeeBJklIywtYaj g.stateGroup rect{fill:#ECECFF;stroke:#9370db}#mermaid-svg-ubOeeBJklIywtYaj g.stateGroup line{stroke:#9370db;stroke-width:1}#mermaid-svg-ubOeeBJklIywtYaj .transition{stroke:#9370db;stroke-width:1;fill:none}#mermaid-svg-ubOeeBJklIywtYaj .stateGroup .composit{fill:white;border-bottom:1px}#mermaid-svg-ubOeeBJklIywtYaj .stateGroup .alt-composit{fill:#e0e0e0;border-bottom:1px}#mermaid-svg-ubOeeBJklIywtYaj .state-note{stroke:#aa3;fill:#fff5ad}#mermaid-svg-ubOeeBJklIywtYaj .state-note text{fill:black;stroke:none;font-size:10px}#mermaid-svg-ubOeeBJklIywtYaj .stateLabel .box{stroke:none;stroke-width:0;fill:#ECECFF;opacity:0.7}#mermaid-svg-ubOeeBJklIywtYaj .edgeLabel text{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .stateLabel text{fill:#000;font-size:10px;font-weight:bold;font-family:'trebuchet ms', verdana, arial;font-family:var(--mermaid-font-family)}#mermaid-svg-ubOeeBJklIywtYaj .node circle.state-start{fill:black;stroke:black}#mermaid-svg-ubOeeBJklIywtYaj .node circle.state-end{fill:black;stroke:white;stroke-width:1.5}#mermaid-svg-ubOeeBJklIywtYaj #statediagram-barbEnd{fill:#9370db}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-cluster rect{fill:#ECECFF;stroke:#9370db;stroke-width:1px}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-cluster rect.outer{rx:5px;ry:5px}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-state .divider{stroke:#9370db}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-state .title-state{rx:5px;ry:5px}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-cluster.statediagram-cluster .inner{fill:white}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-cluster.statediagram-cluster-alt .inner{fill:#e0e0e0}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-cluster .inner{rx:0;ry:0}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-state rect.basic{rx:5px;ry:5px}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-state rect.divider{stroke-dasharray:10,10;fill:#efefef}#mermaid-svg-ubOeeBJklIywtYaj .note-edge{stroke-dasharray:5}#mermaid-svg-ubOeeBJklIywtYaj .statediagram-note rect{fill:#fff5ad;stroke:#aa3;stroke-width:1px;rx:0;ry:0}:root{--mermaid-font-family: '"trebuchet ms", verdana, arial';--mermaid-font-family: "Comic Sans MS", "Comic Sans", cursive}#mermaid-svg-ubOeeBJklIywtYaj .error-icon{fill:#522}#mermaid-svg-ubOeeBJklIywtYaj .error-text{fill:#522;stroke:#522}#mermaid-svg-ubOeeBJklIywtYaj .edge-thickness-normal{stroke-width:2px}#mermaid-svg-ubOeeBJklIywtYaj .edge-thickness-thick{stroke-width:3.5px}#mermaid-svg-ubOeeBJklIywtYaj .edge-pattern-solid{stroke-dasharray:0}#mermaid-svg-ubOeeBJklIywtYaj .edge-pattern-dashed{stroke-dasharray:3}#mermaid-svg-ubOeeBJklIywtYaj .edge-pattern-dotted{stroke-dasharray:2}#mermaid-svg-ubOeeBJklIywtYaj .marker{fill:#333}#mermaid-svg-ubOeeBJklIywtYaj .marker.cross{stroke:#333}:root { --mermaid-font-family: "trebuchet ms", verdana, arial;}#mermaid-svg-ubOeeBJklIywtYaj {color: rgba(0, 0, 0, 0.75);font: ;}

ASCII

不能表示中文

各个国家确认了自己的编规则

中国的是gbk

Unicode

企图把地球上所有的语言都包括进去

表示ASCII码太浪费空间,英国不愿意用

出现UTF-8/UTF-16等编码规则

4.1、编码encode

>>>'字符串'.encode('utf8')
b'\xe5\xad\x97\xe7\xac\xa6\xe4\xb8\xb2'>>> '字符串'.encode('gbk')  #gbk是中国的编码标准
b'\xd7\xd6\xb7\xfb\xb4\xae'

4.2、解码decode

>>> b'\xe5\xad\x97\xe7\xac\xa6\xe4\xb8\xb2'.decode('utf8')
'字符串'
>>> b'\xd7\xd6\xb7\xfb\xb4\xae'.decode('gbk')
'字符串'

Python统一了编码，这样Python在内部处理的时候不会因编码不同而出现程序不能正常执行的问题。

Python会自动根据系统环境选择编码，但是经常在文件传输的过程中，会遇到各种不同的编码，这个时候就需要我们去处理编码问题。

注意：用什么规则编码，就用什么解码