Python学习day19-常用模块之re模块

figure:last-child { margin-bottom: 0.5rem; }
#write ol, #write ul { position: relative; }
img { max-width: 100%; vertical-align: middle; }
button, input, select, textarea { color: inherit; font: inherit; }
input[type="checkbox"], input[type="radio"] { line-height: normal; padding: 0px; }
*, ::after, ::before { box-sizing: border-box; }
#write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p, #write pre { width: inherit; }
#write h1, #write h2, #write h3, #write h4, #write h5, #write h6, #write p { position: relative; }
p { line-height: inherit; }
h1, h2, h3, h4, h5, h6 { break-after: avoid-page; break-inside: avoid; orphans: 2; }
p { orphans: 4; }
h1 { font-size: 2rem; }
h2 { font-size: 1.8rem; }
h3 { font-size: 1.6rem; }
h4 { font-size: 1.4rem; }
h5 { font-size: 1.2rem; }
h6 { font-size: 1rem; }
.md-math-block, .md-rawblock, h1, h2, h3, h4, h5, h6, p { margin-top: 1rem; margin-bottom: 1rem; }
.hidden { display: none; }
.md-blockmeta { color: rgb(204, 204, 204); font-weight: 700; font-style: italic; }
a { cursor: pointer; }
sup.md-footnote { padding: 2px 4px; background-color: rgba(238, 238, 238, 0.7); color: rgb(85, 85, 85); border-radius: 4px; cursor: pointer; }
sup.md-footnote a, sup.md-footnote a:hover { color: inherit; text-transform: inherit; text-decoration: inherit; }
#write input[type="checkbox"] { cursor: pointer; width: inherit; height: inherit; }
figure { overflow-x: auto; margin: 1.2em 0px; max-width: calc(100% + 16px); padding: 0px; }
figure > table { margin: 0px !important; }
tr { break-inside: avoid; break-after: auto; }
thead { display: table-header-group; }
table { border-collapse: collapse; border-spacing: 0px; width: 100%; overflow: auto; break-inside: auto; text-align: left; }
table.md-table td { min-width: 32px; }
.CodeMirror-gutters { border-right: 0px; background-color: inherit; }
.CodeMirror-linenumber { user-select: none; }
.CodeMirror { text-align: left; }
.CodeMirror-placeholder { opacity: 0.3; }
.CodeMirror pre { padding: 0px 4px; }
.CodeMirror-lines { padding: 0px; }
div.hr:focus { cursor: none; }
#write pre { white-space: pre-wrap; }
#write.fences-no-line-wrapping pre { white-space: pre; }
#write pre.ty-contain-cm { white-space: normal; }
.CodeMirror-gutters { margin-right: 4px; }
.md-fences { font-size: 0.9rem; display: block; break-inside: avoid; text-align: left; overflow: visible; white-space: pre; background: inherit; position: relative !important; }
.md-diagram-panel { width: 100%; margin-top: 10px; text-align: center; padding-top: 0px; padding-bottom: 8px; overflow-x: auto; }
#write .md-fences.mock-cm { white-space: pre-wrap; }
.md-fences.md-fences-with-lineno { padding-left: 0px; }
#write.fences-no-line-wrapping .md-fences.mock-cm { white-space: pre; overflow-x: auto; }
.md-fences.mock-cm.md-fences-with-lineno { padding-left: 8px; }
.CodeMirror-line, twitterwidget { break-inside: avoid; }
.footnotes { opacity: 0.8; font-size: 0.9rem; margin-top: 1em; margin-bottom: 1em; }
.footnotes + .footnotes { margin-top: 0px; }
.md-reset { margin: 0px; padding: 0px; border: 0px; outline: 0px; vertical-align: top; background: 0px 0px; text-decoration: none; text-shadow: none; float: none; position: static; width: auto; height: auto; white-space: nowrap; cursor: inherit; -webkit-tap-highlight-color: transparent; line-height: normal; font-weight: 400; text-align: left; box-sizing: content-box; direction: ltr; }
li div { padding-top: 0px; }
blockquote { margin: 1rem 0px; }
li .mathjax-block, li p { margin: 0.5rem 0px; }
li { margin: 0px; position: relative; }
blockquote > :last-child { margin-bottom: 0px; }
blockquote > :first-child, li > :first-child { margin-top: 0px; }
.footnotes-area { color: rgb(136, 136, 136); margin-top: 0.714rem; padding-bottom: 0.143rem; white-space: normal; }
#write .footnote-line { white-space: pre-wrap; }
@media print {
body, html { border: 1px solid transparent; height: 99%; break-after: avoid; break-before: avoid; }
#write { margin-top: 0px; padding-top: 0px; border-color: transparent !important; }
.typora-export * { -webkit-print-color-adjust: exact; }
html.blink-to-pdf { font-size: 13px; }
.typora-export #write { padding-left: 32px; padding-right: 32px; padding-bottom: 0px; break-after: avoid; }
.typora-export #write::after { height: 0px; }
}
.footnote-line { margin-top: 0.714em; font-size: 0.7em; }
a img, img a { cursor: pointer; }
pre.md-meta-block { font-size: 0.8rem; min-height: 0.8rem; white-space: pre-wrap; background: rgb(204, 204, 204); display: block; overflow-x: hidden; }
p > .md-image:only-child:not(.md-img-error) img, p > img:only-child { display: block; margin: auto; }
p > .md-image:only-child { display: inline-block; width: 100%; }
#write .MathJax_Display { margin: 0.8em 0px 0px; }
.md-math-block { width: 100%; }
.md-math-block:not(:empty)::after { display: none; }
[contenteditable="true"]:active, [contenteditable="true"]:focus { outline: 0px; box-shadow: none; }
.md-task-list-item { position: relative; list-style-type: none; }
.task-list-item.md-task-list-item { padding-left: 0px; }
.md-task-list-item > input { position: absolute; top: 0px; left: 0px; margin-left: -1.2em; margin-top: calc(1em - 10px); border: none; }
.math { font-size: 1rem; }
.md-toc { min-height: 3.58rem; position: relative; font-size: 0.9rem; border-radius: 10px; }
.md-toc-content { position: relative; margin-left: 0px; }
.md-toc-content::after, .md-toc::after { display: none; }
.md-toc-item { display: block; color: rgb(65, 131, 196); }
.md-toc-item a { text-decoration: none; }
.md-toc-inner:hover { text-decoration: underline; }
.md-toc-inner { display: inline-block; cursor: pointer; }
.md-toc-h1 .md-toc-inner { margin-left: 0px; font-weight: 700; }
.md-toc-h2 .md-toc-inner { margin-left: 2em; }
.md-toc-h3 .md-toc-inner { margin-left: 4em; }
.md-toc-h4 .md-toc-inner { margin-left: 6em; }
.md-toc-h5 .md-toc-inner { margin-left: 8em; }
.md-toc-h6 .md-toc-inner { margin-left: 10em; }
@media screen and (max-width: 48em) {
.md-toc-h3 .md-toc-inner { margin-left: 3.5em; }
.md-toc-h4 .md-toc-inner { margin-left: 5em; }
.md-toc-h5 .md-toc-inner { margin-left: 6.5em; }
.md-toc-h6 .md-toc-inner { margin-left: 8em; }
}
a.md-toc-inner { font-size: inherit; font-style: inherit; font-weight: inherit; line-height: inherit; }
.footnote-line a:not(.reversefootnote) { color: inherit; }
.md-attr { display: none; }
.md-fn-count::after { content: "."; }
code, pre, samp, tt { font-family: var(--monospace); }
kbd { margin: 0px 0.1em; padding: 0.1em 0.6em; font-size: 0.8em; color: rgb(36, 39, 41); background: rgb(255, 255, 255); border: 1px solid rgb(173, 179, 185); border-radius: 3px; box-shadow: rgba(12, 13, 14, 0.2) 0px 1px 0px, rgb(255, 255, 255) 0px 0px 0px 2px inset; white-space: nowrap; vertical-align: middle; }
.md-comment { color: rgb(162, 127, 3); opacity: 0.8; font-family: var(--monospace); }
code { text-align: left; vertical-align: initial; }
a.md-print-anchor { white-space: pre !important; border-width: initial !important; border-style: none !important; border-color: initial !important; display: inline-block !important; position: absolute !important; width: 1px !important; right: 0px !important; outline: 0px !important; background: 0px 0px !important; text-decoration: initial !important; text-shadow: initial !important; }
.md-inline-math .MathJax_SVG .noError { display: none !important; }
.html-for-mac .inline-math-svg .MathJax_SVG { vertical-align: 0.2px; }
.md-math-block .MathJax_SVG_Display { text-align: center; margin: 0px; position: relative; text-indent: 0px; max-width: none; max-height: none; min-height: 0px; min-width: 100%; width: auto; overflow-y: hidden; display: block !important; }
.MathJax_SVG_Display, .md-inline-math .MathJax_SVG_Display { width: auto; margin: inherit; display: inline-block !important; }
.MathJax_SVG .MJX-monospace { font-family: var(--monospace); }
.MathJax_SVG .MJX-sans-serif { font-family: sans-serif; }
.MathJax_SVG { display: inline; font-style: normal; font-weight: 400; line-height: normal; zoom: 90%; text-indent: 0px; text-align: left; text-transform: none; letter-spacing: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; padding: 0px; margin: 0px; }
.MathJax_SVG * { transition: none 0s ease 0s; }
.MathJax_SVG_Display svg { vertical-align: middle !important; margin-bottom: 0px !important; margin-top: 0px !important; }
.os-windows.monocolor-emoji .md-emoji { font-family: "Segoe UI Symbol", sans-serif; }
.md-diagram-panel > svg { max-width: 100%; }
[lang="mermaid"] svg, [lang="flow"] svg { max-width: 100%; height: auto; }
[lang="mermaid"] .node text { font-size: 1rem; }
table tr th { border-bottom: 0px; }
video { max-width: 100%; display: block; margin: 0px auto; }
iframe { max-width: 100%; width: 100%; border: none; }
.highlight td, .highlight tr { border: 0px; }

.CodeMirror { height: auto; }
.CodeMirror.cm-s-inner { background: inherit; }
.CodeMirror-scroll { overflow: auto hidden; z-index: 3; }
.CodeMirror-gutter-filler, .CodeMirror-scrollbar-filler { background-color: rgb(255, 255, 255); }
.CodeMirror-gutters { border-right: 1px solid rgb(221, 221, 221); background: inherit; white-space: nowrap; }
.CodeMirror-linenumber { padding: 0px 3px 0px 5px; text-align: right; color: rgb(153, 153, 153); }
.cm-s-inner .cm-keyword { color: rgb(119, 0, 136); }
.cm-s-inner .cm-atom, .cm-s-inner.cm-atom { color: rgb(34, 17, 153); }
.cm-s-inner .cm-number { color: rgb(17, 102, 68); }
.cm-s-inner .cm-def { color: rgb(0, 0, 255); }
.cm-s-inner .cm-variable { color: rgb(0, 0, 0); }
.cm-s-inner .cm-variable-2 { color: rgb(0, 85, 170); }
.cm-s-inner .cm-variable-3 { color: rgb(0, 136, 85); }
.cm-s-inner .cm-string { color: rgb(170, 17, 17); }
.cm-s-inner .cm-property { color: rgb(0, 0, 0); }
.cm-s-inner .cm-operator { color: rgb(152, 26, 26); }
.cm-s-inner .cm-comment, .cm-s-inner.cm-comment { color: rgb(170, 85, 0); }
.cm-s-inner .cm-string-2 { color: rgb(255, 85, 0); }
.cm-s-inner .cm-meta { color: rgb(85, 85, 85); }
.cm-s-inner .cm-qualifier { color: rgb(85, 85, 85); }
.cm-s-inner .cm-builtin { color: rgb(51, 0, 170); }
.cm-s-inner .cm-bracket { color: rgb(153, 153, 119); }
.cm-s-inner .cm-tag { color: rgb(17, 119, 0); }
.cm-s-inner .cm-attribute { color: rgb(0, 0, 204); }
.cm-s-inner .cm-header, .cm-s-inner.cm-header { color: rgb(0, 0, 255); }
.cm-s-inner .cm-quote, .cm-s-inner.cm-quote { color: rgb(0, 153, 0); }
.cm-s-inner .cm-hr, .cm-s-inner.cm-hr { color: rgb(153, 153, 153); }
.cm-s-inner .cm-link, .cm-s-inner.cm-link { color: rgb(0, 0, 204); }
.cm-negative { color: rgb(221, 68, 68); }
.cm-positive { color: rgb(34, 153, 34); }
.cm-header, .cm-strong { font-weight: 700; }
.cm-del { text-decoration: line-through; }
.cm-em { font-style: italic; }
.cm-link { text-decoration: underline; }
.cm-error { color: red; }
.cm-invalidchar { color: red; }
.cm-constant { color: rgb(38, 139, 210); }
.cm-defined { color: rgb(181, 137, 0); }
div.CodeMirror span.CodeMirror-matchingbracket { color: rgb(0, 255, 0); }
div.CodeMirror span.CodeMirror-nonmatchingbracket { color: rgb(255, 34, 34); }
.cm-s-inner .CodeMirror-activeline-background { background: inherit; }
.CodeMirror { position: relative; overflow: hidden; }
.CodeMirror-scroll { height: 100%; outline: 0px; position: relative; box-sizing: content-box; background: inherit; }
.CodeMirror-sizer { position: relative; }
.CodeMirror-gutter-filler, .CodeMirror-hscrollbar, .CodeMirror-scrollbar-filler, .CodeMirror-vscrollbar { position: absolute; z-index: 6; display: none; }
.CodeMirror-vscrollbar { right: 0px; top: 0px; overflow: hidden; }
.CodeMirror-hscrollbar { bottom: 0px; left: 0px; overflow: hidden; }
.CodeMirror-scrollbar-filler { right: 0px; bottom: 0px; }
.CodeMirror-gutter-filler { left: 0px; bottom: 0px; }
.CodeMirror-gutters { position: absolute; left: 0px; top: 0px; padding-bottom: 30px; z-index: 3; }
.CodeMirror-gutter { white-space: normal; height: 100%; box-sizing: content-box; padding-bottom: 30px; margin-bottom: -32px; display: inline-block; }
.CodeMirror-gutter-wrapper { position: absolute; z-index: 4; background: 0px 0px !important; border: none !important; }
.CodeMirror-gutter-background { position: absolute; top: 0px; bottom: 0px; z-index: 4; }
.CodeMirror-gutter-elt { position: absolute; cursor: default; z-index: 4; }
.CodeMirror-lines { cursor: text; }
.CodeMirror pre { border-radius: 0px; border-width: 0px; background: 0px 0px; font-family: inherit; font-size: inherit; margin: 0px; white-space: pre; overflow-wrap: normal; color: inherit; z-index: 2; position: relative; overflow: visible; }
.CodeMirror-wrap pre { overflow-wrap: break-word; white-space: pre-wrap; word-break: normal; }
.CodeMirror-code pre { border-right: 30px solid transparent; width: fit-content; }
.CodeMirror-wrap .CodeMirror-code pre { border-right: none; width: auto; }
.CodeMirror-linebackground { position: absolute; left: 0px; right: 0px; top: 0px; bottom: 0px; z-index: 0; }
.CodeMirror-linewidget { position: relative; z-index: 2; overflow: auto; }
.CodeMirror-wrap .CodeMirror-scroll { overflow-x: hidden; }
.CodeMirror-measure { position: absolute; width: 100%; height: 0px; overflow: hidden; visibility: hidden; }
.CodeMirror-measure pre { position: static; }
.CodeMirror div.CodeMirror-cursor { position: absolute; visibility: hidden; border-right: none; width: 0px; }
.CodeMirror div.CodeMirror-cursor { visibility: hidden; }
.CodeMirror-focused div.CodeMirror-cursor { visibility: inherit; }
.cm-searching { background: rgba(255, 255, 0, 0.4); }
@media print {
.CodeMirror div.CodeMirror-cursor { visibility: hidden; }
}

:root { --side-bar-bg-color: #fafafa; --control-text-color: #777; }
html { font-size: 16px; }
body { font-family: "Open Sans", "Clear Sans", "Helvetica Neue", Helvetica, Arial, sans-serif; color: rgb(51, 51, 51); line-height: 1.6; }
#write { max-width: 860px; margin: 0px auto; padding: 30px 30px 100px; }
#write > ul:first-child, #write > ol:first-child { margin-top: 30px; }
a { color: rgb(65, 131, 196); }
h1, h2, h3, h4, h5, h6 { position: relative; margin-top: 1rem; margin-bottom: 1rem; font-weight: bold; line-height: 1.4; cursor: text; }
h1:hover a.anchor, h2:hover a.anchor, h3:hover a.anchor, h4:hover a.anchor, h5:hover a.anchor, h6:hover a.anchor { text-decoration: none; }
h1 tt, h1 code { font-size: inherit; }
h2 tt, h2 code { font-size: inherit; }
h3 tt, h3 code { font-size: inherit; }
h4 tt, h4 code { font-size: inherit; }
h5 tt, h5 code { font-size: inherit; }
h6 tt, h6 code { font-size: inherit; }
h1 { padding-bottom: 0.3em; font-size: 2.25em; line-height: 1.2; border-bottom: 1px solid rgb(238, 238, 238); }
h2 { padding-bottom: 0.3em; font-size: 1.75em; line-height: 1.225; border-bottom: 1px solid rgb(238, 238, 238); }
h3 { font-size: 1.5em; line-height: 1.43; }
h4 { font-size: 1.25em; }
h5 { font-size: 1em; }
h6 { font-size: 1em; color: rgb(119, 119, 119); }
p, blockquote, ul, ol, dl, table { margin: 0.8em 0px; }
li > ol, li > ul { margin: 0px; }
hr { height: 2px; padding: 0px; margin: 16px 0px; background-color: rgb(231, 231, 231); border: 0px none; overflow: hidden; box-sizing: content-box; }
li p.first { display: inline-block; }
ul, ol { padding-left: 30px; }
ul:first-child, ol:first-child { margin-top: 0px; }
ul:last-child, ol:last-child { margin-bottom: 0px; }
blockquote { border-left: 4px solid rgb(223, 226, 229); padding: 0px 15px; color: rgb(119, 119, 119); }
blockquote blockquote { padding-right: 0px; }
table { padding: 0px; word-break: initial; }
table tr { border-top: 1px solid rgb(223, 226, 229); margin: 0px; padding: 0px; }
table tr:nth-child(2n), thead { background-color: rgb(248, 248, 248); }
table tr th { font-weight: bold; border-width: 1px 1px 0px; border-top-style: solid; border-right-style: solid; border-left-style: solid; border-top-color: rgb(223, 226, 229); border-right-color: rgb(223, 226, 229); border-left-color: rgb(223, 226, 229); border-image: initial; border-bottom-style: initial; border-bottom-color: initial; margin: 0px; padding: 6px 13px; }
table tr td { border: 1px solid rgb(223, 226, 229); margin: 0px; padding: 6px 13px; }
table tr th:first-child, table tr td:first-child { margin-top: 0px; }
table tr th:last-child, table tr td:last-child { margin-bottom: 0px; }
.CodeMirror-lines { padding-left: 4px; }
.code-tooltip { box-shadow: rgba(0, 28, 36, 0.3) 0px 1px 1px 0px; border-top: 1px solid rgb(238, 242, 242); }
.md-fences, code, tt { border: 1px solid rgb(231, 234, 237); background-color: rgb(248, 248, 248); border-radius: 3px; padding: 2px 4px 0px; font-size: 0.9em; }
code { background-color: rgb(243, 244, 244); padding: 0px 2px; }
.md-fences { margin-bottom: 15px; margin-top: 15px; padding-top: 8px; padding-bottom: 6px; }
.md-task-list-item > input { margin-left: -1.3em; }
@media print {
html { font-size: 13px; }
table, pre { break-inside: avoid; }
pre { overflow-wrap: break-word; }
}
.md-fences { background-color: rgb(248, 248, 248); }
#write pre.md-meta-block { padding: 1rem; font-size: 85%; line-height: 1.45; background-color: rgb(247, 247, 247); border: 0px; border-radius: 3px; color: rgb(119, 119, 119); margin-top: 0px !important; }
.mathjax-block > .code-tooltip { bottom: 0.375rem; }
.md-mathjax-midline { background: rgb(250, 250, 250); }
#write > h3.md-focus::before { left: -1.5625rem; top: 0.375rem; }
#write > h4.md-focus::before { left: -1.5625rem; top: 0.285714rem; }
#write > h5.md-focus::before { left: -1.5625rem; top: 0.285714rem; }
#write > h6.md-focus::before { left: -1.5625rem; top: 0.285714rem; }
.md-image > .md-meta { border-radius: 3px; padding: 2px 0px 0px 4px; font-size: 0.9em; color: inherit; }
.md-tag { color: rgb(167, 167, 167); opacity: 1; }
.md-toc { margin-top: 20px; padding-bottom: 20px; }
.sidebar-tabs { border-bottom: none; }
#typora-quick-open { border: 1px solid rgb(221, 221, 221); background-color: rgb(248, 248, 248); }
#typora-quick-open-item { background-color: rgb(250, 250, 250); border-color: rgb(254, 254, 254) rgb(229, 229, 229) rgb(229, 229, 229) rgb(238, 238, 238); border-style: solid; border-width: 1px; }
.on-focus-mode blockquote { border-left-color: rgba(85, 85, 85, 0.12); }
header, .context-menu, .megamenu-content, footer { font-family: "Segoe UI", Arial, sans-serif; }
.file-node-content:hover .file-node-icon, .file-node-content:hover .file-node-open-state { visibility: visible; }
.mac-seamless-mode #typora-sidebar { background-color: var(--side-bar-bg-color); }
.md-lang { color: rgb(180, 101, 77); }
.html-for-mac .context-menu { --item-hover-bg-color: #E6F0FE; }
#md-notification .btn { border: 0px; }
.dropdown-menu .divider { border-color: rgb(229, 229, 229); }
.ty-preferences .window-content { background-color: rgb(250, 250, 250); }
.ty-preferences .nav-group-item.active { color: white; background: rgb(153, 153, 153); }
-->

Python学习day19-常用模块之re模块正则表达式re的基本语法(匹配规则)：

Python学习day19-常用模块之re模块

正则表达式

正则表达式我们应该或多或少都听过，因为这并不是python所独有的东西，而是一个比较广泛的概念。简单来说正则表达式就是从字符串里寻找特定的字符串，通过各种通配符和表达式。在Python中，正则表达式通过内嵌集成成为一个re模块，就是用来实现正则表达式的各种功能。

正则表达式的大致匹配过程是：依次拿出表达式中的字符来和文本中的字符进行比较，如果每一个字符都能匹配，则匹配成功，一旦有匹配不成功的字符则匹配失败。且一旦匹配成功就会跳过这个字符，并不会重复取值。

re的基本语法(匹配规则)：

re的语法很多，我们这里只介绍比较常用的一部分语法的用法：

 

 

 

xxxxxxxxxx

136

 

 

 

 

1

import re

2

​

3

s = '王大炮打炮被大炮打死了王大炮打炮被大炮打死了'

4

# 正常情况下，如果我们想要取出'大炮'这个字符只能用一下这种方法

5

print(s[1:3], s[6:8])

6

​

7

# 可见这非常的复杂，而且非常low

8

​

9

# 所以调用re模块来做的话，就像以下这样

10

​

11

res = re.findall('大炮',s)

12

print(res)# 这样我们就可以直接找到字符串里的所有‘大炮’的字符

13

​

14

# 另外还有一些别的用法

15

​

16

# ^:判定开头，注意要放在字符串前面，不会往后寻找，只会判定开头

17

print(re.findall('^王大炮', s))

18

# 即返回结果'王大炮'，因为字符串开头就是王大炮

19

​

20

# $:结尾，要注意放在字符串后面，和^相反

21

print(re.findall('死了$', s))

22

#返回结果是'死了'

23

​

24

# []:匹配中间的字符

25

s = 'abcdef'

26

print(re.findall('[ace]', s))  # 只要单个字符

27

# ['a', 'c', 'e']

28

# 返回的是分开的单个字符，且只要单个字符

29

​

30

# []+^:取反，^对[]内的元素，除了这些字符，输出其余的

31

print(re.findall('[^acef]', s))

32

# ['b','d']

33

​

34

# .：任意单个字符（除了换行符\n，如果需要取换行符，需要在字符串前面加r）

35

s = 'ababadaeaf'

36

print(re.findall('a.', s))

37

print(re.findall('a..', s))

38

# ['ab', 'ab', 'ad', 'ae', 'af']

39

# ['aba', 'ada']这个结果说明字符串里取过的字符不会重复取，只会取第一次

40

​

41

# *:可以替代字符0-无穷，都取出来，中间是空字符

42

s = 'abaacaaaaa'

43

print(re.findall('a*',s))

44

# ['a', '', 'aa', '', 'aaaaa', '']即但凡有a的地方都输出，没有的话就返回空数据

45

​

46

# +：前面的字符1-无穷，都取出来

47

print(re.findall('a+',s))

48

# ['a', 'aa', 'aaaaa']这种情况不存在空的情况，即最少为1个字符才会进行输出

49

​

50

# ?:前面的字符0-1个，即输出的都是单个字符，如果不是给定值，就返回空值

51

print(re.findall('a?',s))

52

# ['a', '', 'a', 'a', '', 'a', 'a', 'a', 'a', 'a', '']

53

​

54

# {m}：前面的字符m个，括号里的数字即为保留的位数，所以输出是5个a，如果字符串里没有五个a，就会输出空

55

print(re.findall('a{5}',s))

56

# ['aaaaa']

57

​

58

# {n,m}:前面的字符2-3个

59

print(re.findall('a{2,3}', s))# 会往最大的m取，最小n为才会输出

60

# ['aa', 'aaa', 'aa']#会取最大的m，也就是说如果字符串里有长度超过m的字符，只会返回长度为m的，也就是三位的，然后重新计数。

61

​

62

# \d:数字

63

s = 's1+s*2-s+3/'

64

print(re.findall('\d',s))# 只会输出字符串内的数字类型

65

# ['1','2','3']

66

​

67

# \D:非数字

68

print(re.findall('\D',s))# 不会输出数字类型，其余均取出

69

# ['s', '+', 's', '*', '-', 's', '+', '/']

70

​

71

# \w:数字/字符/下划线 都会取出来

72

print(re.findall('\w',s))

73

# ['s','1','s','2','s','3']

74

​

75

# \W:非数字/字符/下划线 取出来

76

print(re.findall('\W',s))

77

# ['+','*','-','+','/']

78

​

79

# \s:空格/t/n

80

s = 'avc sdf fe'

81

print(re.findall('\s',s))

82

# ['','']

83

​

84

# \S:非 空格/t/n

85

print(re.findall('\S',s))

86

# ['a','v',c','s','d','f','f','e']

87

​

88

# \:把后面的字符取消特殊意义

89

s = 'aba\d'

90

print(re.findall(r'\\d', s))

91

# ['\\d']

92

​

93

# .*:有什么都要,贪婪，结果最大化

94

s = 'abcabc'

95

print(re.findall('a.*c', s))

96

# ['abcabc']

97

​

98

# .*?:非贪婪，最小化，找到符合条件就停止,*********这个应该是以后用的最多的正则表达式

99

print(re.findall('a.*?c', s))

100

# ['abc','abc']

101

​

102

# ()：匹配到结果后只要括号内的，不要外面的，但匹配的时候条件是要全引号里的

103

s = 'abacad'

104

print(re.findall('a(.)', s))#点表示a后面的一个字符，加括号表示只显示这一个字符

105

# ['b','c','d']

106

​

107

# A|B：A和B都要

108

print(re.findall('a|b', s))# a和b都要，单字符值

109

# ['a','b','a','a']

110

​

111

# re模块的方法

112

​

113

# re.complie，根据包含的正则表达式的字符串创建模式对象。

114

s = 'abc123def\n456'

115

print(re.findall('\d+', s))

116

com = re.compile('f.')

117

print(re.findall(com, s))

118

# ['123','456']

119

# []

120

​

121

# re.S:匹配里面的所有字符，包括换行

122

print(re.findall('f.', s, re.S))

123

# ['f\n']

124

​

125

# re.match()：从开头搜索，搜索到了就是有，没搜索到就是None

126

s = 'abc'

127

res = re.match('\d+',s)

128

print(res)

129

res.group()

130

​

131

# re.search():搜索第一个搜索结果，找到即停止

132

re0s = re.search('\d+',s)

133

print(res)

134

print(res.group())

135

​

136

# re.split():以匹配规则来切割

137

s = 'abc534adf235sdf4'

138

print(re.split('\d+', s))

139

​

140

# re.sub（）：按照匹配规则来替换**************************重要

141

print(re.sub('\d+','***',s))

142

​

143

# re.subn():按照匹配规则替换，并计数

144

print(re.subn('\d+','***',s))

145

​

146

# 分组:一个括号叫一个分组,并给每个分组起名,key:value?,django里URL分组

147

s = 'abc123edf456'

148

res = re.search('abc(?P<abc>\d+)edf(?P<edf>\d+)', s)

149

print(res.groupdict())