3. \u6b63\u5219\u8868\u8fbe\u5f0f\u5b9a\u4e49\r\n <\/p>
\u3000\u3000\u6b63\u5219\u8868\u8fbe\u5f0f(regular expression)\u63cf\u8ff0\u4e86\u4e00\u79cd\u5b57\u7b26\u4e32\u5339\u914d\u7684\u6a21\u5f0f\uff0c\u53ef\u4ee5\u7528\u6765\u68c0\u67e5\u4e00\u4e2a\u4e32\u662f\u5426\u542b\u6709\u67d0\u79cd\u5b50\u4e32\u3001\u5c06\u5339\u914d\u7684\u5b50\u4e32\u505a\u66ff\u6362\u6216\u8005\u4ece\u67d0\u4e2a\u4e32\u4e2d\u53d6\u51fa\u7b26\u5408\u67d0\u4e2a\u6761\u4ef6\u7684\u5b50\u4e32\u7b49\u3002<\/p>
\u5217\u76ee\u5f55\u65f6\uff0c\u3000dir *.txt\u6216ls *.txt\u4e2d\u7684*.txt\u5c31\u4e0d\u662f\u4e00\u4e2a\u6b63\u5219\u8868\u8fbe\u5f0f,\u56e0\u4e3a\u8fd9\u91cc*\u4e0e\u6b63\u5219\u5f0f\u7684*\u7684\u542b\u4e49\u662f\u4e0d\u540c\u7684\u3002<\/p><\/li><\/ul><\/p>
\u3000\u3000\u6b63\u5219\u8868\u8fbe\u5f0f\u662f\u7531\u666e\u901a\u5b57\u7b26\uff08\u4f8b\u5982\u5b57\u7b26 a \u5230 z\uff09\u4ee5\u53ca\u7279\u6b8a\u5b57\u7b26\uff08\u79f0\u4e3a\u5143\u5b57\u7b26\uff09\u7ec4\u6210\u7684\u6587\u5b57\u6a21\u5f0f\u3002\u6b63\u5219\u8868\u8fbe\u5f0f\u4f5c\u4e3a\u4e00\u4e2a\u6a21\u677f\uff0c\u5c06\u67d0\u4e2a\u5b57\u7b26\u6a21\u5f0f\u4e0e\u6240\u641c\u7d22\u7684\u5b57\u7b26\u4e32\u8fdb\u884c\u5339\u914d\u3002<\/p>
3.1 \u666e\u901a\u5b57\u7b26\r\n <\/p>
\u3000\u3000\u7531\u6240\u6709\u90a3\u4e9b\u672a\u663e\u5f0f\u6307\u5b9a\u4e3a\u5143\u5b57\u7b26\u7684\u6253\u5370\u548c\u975e\u6253\u5370\u5b57\u7b26\u7ec4\u6210\u3002\u8fd9\u5305\u62ec\u6240\u6709\u7684\u5927\u5199\u548c\u5c0f\u5199\u5b57\u6bcd\u5b57\u7b26\uff0c\u6240\u6709\u6570\u5b57\uff0c\u6240\u6709\u6807\u70b9\u7b26\u53f7\u4ee5\u53ca\u4e00\u4e9b\u7b26\u53f7\u3002<\/p>
3.2 \u975e\u6253\u5370\u5b57\u7b26\r\n <\/p>
<\/p>
\u5b57\u7b26<\/p>
\u542b\u4e49<\/p>
<\/p>
\\cx \u5339\u914d\u7531x\u6307\u660e\u7684\u63a7\u5236\u5b57\u7b26\u3002\u4f8b\u5982\uff0c \\cM \u5339\u914d\u4e00\u4e2a Control-M \u6216\u56de\u8f66\u7b26\u3002x \u7684\u503c\u5fc5\u987b\u4e3a A-Z \u6216 a-z \u4e4b\u4e00\u3002\u5426\u5219\uff0c\u5c06 c \u89c6\u4e3a\u4e00\u4e2a\u539f\u4e49\u7684 'c' \u5b57\u7b26\u3002 <\/p>
\\f \u5339\u914d\u4e00\u4e2a\u6362\u9875\u7b26\u3002\u7b49\u4ef7\u4e8e \\x0c \u548c \\cL\u3002 <\/p>
\\n \u5339\u914d\u4e00\u4e2a\u6362\u884c\u7b26\u3002\u7b49\u4ef7\u4e8e \\x0a \u548c \\cJ\u3002 <\/p>
\\r \u5339\u914d\u4e00\u4e2a\u56de\u8f66\u7b26\u3002\u7b49\u4ef7\u4e8e \\x0d \u548c \\cM\u3002 <\/p>
\\s \u5339\u914d\u4efb\u4f55\u7a7a\u767d\u5b57\u7b26\uff0c\u5305\u62ec\u7a7a\u683c\u3001\u5236\u8868\u7b26\u3001\u6362\u9875\u7b26\u7b49\u7b49\u3002\u7b49\u4ef7\u4e8e [ \\f\\n\\r\\t\\v]\u3002 <\/p>
\\S \u5339\u914d\u4efb\u4f55\u975e\u7a7a\u767d\u5b57\u7b26\u3002\u7b49\u4ef7\u4e8e [^ \\f\\n\\r\\t\\v]\u3002 <\/p>
\\t \u5339\u914d\u4e00\u4e2a\u5236\u8868\u7b26\u3002\u7b49\u4ef7\u4e8e \\x09 \u548c \\cI\u3002 <\/p>
\\v \u5339\u914d\u4e00\u4e2a\u5782\u76f4\u5236\u8868\u7b26\u3002\u7b49\u4ef7\u4e8e \\x0b \u548c \\cK\u3002 <\/p>
\u3000\u3000 \u6240\u8c13\u7279\u6b8a\u5b57\u7b26\uff0c\u5c31\u662f\u4e00\u4e9b\u6709\u7279\u6b8a\u542b\u4e49\u7684\u5b57\u7b26\uff0c\u5982\u4e0a\u9762\u8bf4\u7684"*.txt"\u4e2d\u7684*\uff0c\u7b80\u5355\u7684\u8bf4\u5c31\u662f\u8868\u793a\u4efb\u4f55\u5b57\u7b26\u4e32\u7684\u610f\u601d\u3002\u5982\u679c\u8981\u67e5\u627e\u6587\u4ef6\u540d\u4e2d\u6709\uff0a\u7684\u6587\u4ef6\uff0c\u5219\u9700\u8981\u5bf9\uff0a\u8fdb\u884c\u8f6c\u4e49\uff0c\u5373\u5728\u5176\u524d\u52a0\u4e00\u4e2a\\\u3002ls \\*.txt\u3002\u6b63\u5219\u8868\u8fbe\u5f0f\u6709\u4ee5\u4e0b\u7279\u6b8a\u5b57\u7b26\u3002<\/p>
\u3000<\/p>
<\/p>
\u7279\u522b\u5b57\u7b26<\/p>
\u8bf4\u660e<\/p>
<\/p>
$ \u5339\u914d\u8f93\u5165\u5b57\u7b26\u4e32\u7684\u7ed3\u5c3e\u4f4d\u7f6e\u3002\u5982\u679c\u8bbe\u7f6e\u4e86 RegExp \u5bf9\u8c61\u7684 Multiline \u5c5e\u6027\uff0c\u5219 $ \u4e5f\u5339\u914d '\\n' \u6216 '\\r'\u3002\u8981\u5339\u914d $ \u5b57\u7b26\u672c\u8eab\uff0c\u8bf7\u4f7f\u7528 \\$\u3002 <\/p>
( ) \u6807\u8bb0\u4e00\u4e2a\u5b50\u8868\u8fbe\u5f0f\u7684\u5f00\u59cb\u548c\u7ed3\u675f\u4f4d\u7f6e\u3002\u5b50\u8868\u8fbe\u5f0f\u53ef\u4ee5\u83b7\u53d6\u4f9b\u4ee5\u540e\u4f7f\u7528\u3002\u8981\u5339\u914d\u8fd9\u4e9b\u5b57\u7b26\uff0c\u8bf7\u4f7f\u7528 \\( \u548c \\)\u3002 <\/p>
* \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u96f6\u6b21\u6216\u591a\u6b21\u3002\u8981\u5339\u914d * \u5b57\u7b26\uff0c\u8bf7\u4f7f\u7528 \\*\u3002 <\/p>
+ \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u4e00\u6b21\u6216\u591a\u6b21\u3002\u8981\u5339\u914d + \u5b57\u7b26\uff0c\u8bf7\u4f7f\u7528 \\+\u3002 <\/p>
. \u5339\u914d\u9664\u6362\u884c\u7b26 \\n\u4e4b\u5916\u7684\u4efb\u4f55\u5355\u5b57\u7b26\u3002\u8981\u5339\u914d .\uff0c\u8bf7\u4f7f\u7528 \\\u3002 <\/p>
[ \u6807\u8bb0\u4e00\u4e2a\u4e2d\u62ec\u53f7\u8868\u8fbe\u5f0f\u7684\u5f00\u59cb\u3002\u8981\u5339\u914d [\uff0c\u8bf7\u4f7f\u7528 \\[\u3002 <\/p>
? \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u96f6\u6b21\u6216\u4e00\u6b21\uff0c\u6216\u6307\u660e\u4e00\u4e2a\u975e\u8d2a\u5a6a\u9650\u5b9a\u7b26\u3002\u8981\u5339\u914d ? \u5b57\u7b26\uff0c\u8bf7\u4f7f\u7528 \\?\u3002 <\/p>
\\ \u5c06\u4e0b\u4e00\u4e2a\u5b57\u7b26\u6807\u8bb0\u4e3a\u6216\u7279\u6b8a\u5b57\u7b26\u3001\u6216\u539f\u4e49\u5b57\u7b26\u3001\u6216\u5411\u540e\u5f15\u7528\u3001\u6216\u516b\u8fdb\u5236\u8f6c\u4e49\u7b26\u3002\u4f8b\u5982\uff0c 'n' \u5339\u914d\u5b57\u7b26 'n'\u3002'\\n' \u5339\u914d\u6362\u884c\u7b26\u3002\u5e8f\u5217 '\\\\' \u5339\u914d "\\"\uff0c\u800c '\\(' \u5219\u5339\u914d "("\u3002 <\/p>
^ \u5339\u914d\u8f93\u5165\u5b57\u7b26\u4e32\u7684\u5f00\u59cb\u4f4d\u7f6e\uff0c\u9664\u975e\u5728\u65b9\u62ec\u53f7\u8868\u8fbe\u5f0f\u4e2d\u4f7f\u7528\uff0c\u6b64\u65f6\u5b83\u8868\u793a\u4e0d\u63a5\u53d7\u8be5\u5b57\u7b26\u96c6\u5408\u3002\u8981\u5339\u914d ^ \u5b57\u7b26\u672c\u8eab\uff0c\u8bf7\u4f7f\u7528 \\^\u3002 <\/p>
{ \u6807\u8bb0\u9650\u5b9a\u7b26\u8868\u8fbe\u5f0f\u7684\u5f00\u59cb\u3002\u8981\u5339\u914d {\uff0c\u8bf7\u4f7f\u7528 \\{\u3002 <\/p>
| \u6307\u660e\u4e24\u9879\u4e4b\u95f4\u7684\u4e00\u4e2a\u9009\u62e9\u3002\u8981\u5339\u914d |\uff0c\u8bf7\u4f7f\u7528 \\|\u3002 <\/p>
\u3000\u3000\u6784\u9020\u6b63\u5219\u8868\u8fbe\u5f0f\u7684\u65b9\u6cd5\u548c\u521b\u5efa\u6570\u5b66\u8868\u8fbe\u5f0f\u7684\u65b9\u6cd5\u4e00\u6837\u3002\u4e5f\u5c31\u662f\u7528\u591a\u79cd\u5143\u5b57\u7b26\u4e0e\u64cd\u4f5c\u7b26\u5c06\u5c0f\u7684\u8868\u8fbe\u5f0f\u7ed3\u5408\u5728\u4e00\u8d77\u6765\u521b\u5efa\u66f4\u5927\u7684\u8868\u8fbe\u5f0f\u3002\u6b63\u5219\u8868\u8fbe\u5f0f\u7684\u7ec4\u4ef6\u53ef\u4ee5\u662f\u5355\u4e2a\u7684\u5b57\u7b26\u3001\u5b57\u7b26\u96c6\u5408\u3001\u5b57\u7b26\u8303\u56f4\u3001\u5b57\u7b26\u95f4\u7684\u9009\u62e9\u6216\u8005\u6240\u6709\u8fd9\u4e9b\u7ec4\u4ef6\u7684\u4efb\u610f\u7ec4\u5408\u3002<\/p><\/li><\/ul><\/p>
\u3000<\/p>
3.4 \u9650\u5b9a\u7b26<\/p>
\u3000\u3000 \u9650\u5b9a\u7b26\u7528\u6765\u6307\u5b9a\u6b63\u5219\u8868\u8fbe\u5f0f\u7684\u4e00\u4e2a\u7ed9\u5b9a\u7ec4\u4ef6\u5fc5\u987b\u8981\u51fa\u73b0\u591a\u5c11\u6b21\u624d\u80fd\u6ee1\u8db3\u5339\u914d\u3002\u6709*\u6216+\u6216?\u6216{n}\u6216{n,}\u6216{n,m}\u51716\u79cd\u3002
<\/p>
\u5b57\u7b26<\/p>
\u63cf\u8ff0<\/p>
<\/p>
* \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u96f6\u6b21\u6216\u591a\u6b21\u3002\u4f8b\u5982\uff0czo* \u80fd\u5339\u914d "z" \u4ee5\u53ca "zoo"\u3002* \u7b49\u4ef7\u4e8e{0,}\u3002 <\/p>
+ \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u4e00\u6b21\u6216\u591a\u6b21\u3002\u4f8b\u5982\uff0c'zo+' \u80fd\u5339\u914d "zo" \u4ee5\u53ca "zoo"\uff0c\u4f46\u4e0d\u80fd\u5339\u914d "z"\u3002+ \u7b49\u4ef7\u4e8e {1,}\u3002 <\/p>
? \u5339\u914d\u524d\u9762\u7684\u5b50\u8868\u8fbe\u5f0f\u96f6\u6b21\u6216\u4e00\u6b21\u3002\u4f8b\u5982\uff0c"do(es)?" \u53ef\u4ee5\u5339\u914d "do" \u6216 "does" \u4e2d\u7684"do" \u3002? \u7b49\u4ef7\u4e8e {0,1}\u3002 <\/p>
{n} n \u662f\u4e00\u4e2a\u975e\u8d1f\u6574\u6570\u3002\u5339\u914d\u786e\u5b9a\u7684 n \u6b21\u3002\u4f8b\u5982\uff0c'o{2}' \u4e0d\u80fd\u5339\u914d "Bob" \u4e2d\u7684 'o'\uff0c\u4f46\u662f\u80fd\u5339\u914d "food" \u4e2d\u7684\u4e24\u4e2a o\u3002 <\/p>
{n,} n \u662f\u4e00\u4e2a\u975e\u8d1f\u6574\u6570\u3002\u81f3\u5c11\u5339\u914dn \u6b21\u3002\u4f8b\u5982\uff0c'o{2,}' \u4e0d\u80fd\u5339\u914d "Bob" \u4e2d\u7684 'o'\uff0c\u4f46\u80fd\u5339\u914d "foooood" \u4e2d\u7684\u6240\u6709 o\u3002'o{1,}' \u7b49\u4ef7\u4e8e 'o+'\u3002'o{0,}' \u5219\u7b49\u4ef7\u4e8e 'o*'\u3002 <\/p>
{n,m} m \u548c n \u5747\u4e3a\u975e\u8d1f\u6574\u6570\uff0c\u5176\u4e2dn <= m\u3002\u6700\u5c11\u5339\u914d n \u6b21\u4e14\u6700\u591a\u5339\u914d m \u6b21\u3002\u4f8b\u5982\uff0c"o{1,3}" \u5c06\u5339\u914d "fooooood" \u4e2d\u7684\u524d\u4e09\u4e2a o\u3002'o{0,1}' \u7b49\u4ef7\u4e8e 'o?'\u3002\u8bf7\u6ce8\u610f\u5728\u9017\u53f7\u548c\u4e24\u4e2a\u6570\u4e4b\u95f4\u4e0d\u80fd\u6709\u7a7a\u683c\u3002 <\/p>
3.5 \u5b9a\u4f4d\u7b26<\/p>
\u3000\u3000 \u7528\u6765\u63cf\u8ff0\u5b57\u7b26\u4e32\u6216\u5355\u8bcd\u7684\u8fb9\u754c\uff0c^\u548c$\u5206\u522b\u6307\u5b57\u7b26\u4e32\u7684\u5f00\u59cb\u4e0e\u7ed3\u675f\uff0c\\b\u63cf\u8ff0\u5355\u8bcd\u7684\u524d\u6216\u540e\u8fb9\u754c\uff0c\\B\u8868\u793a\u975e\u5355\u8bcd\u8fb9\u754c\u3002\u4e0d\u80fd\u5bf9\u5b9a\u4f4d\u7b26\u4f7f\u7528\u9650\u5b9a\u7b26\u3002\r\n <\/p>
3.6 \u9009\u62e9<\/p>
\u3000\u3000 \u7528\u5706\u62ec\u53f7\u5c06\u6240\u6709\u9009\u62e9\u9879\u62ec\u8d77\u6765\uff0c\u76f8\u90bb\u7684\u9009\u62e9\u9879\u4e4b\u95f4\u7528|\u5206\u9694\u3002\u4f46\u7528\u5706\u62ec\u53f7\u4f1a\u6709\u4e00\u4e2a\u526f\u4f5c\u7528\uff0c\u662f\u76f8\u5173\u7684\u5339\u914d\u4f1a\u88ab\u7f13\u5b58\uff0c\u6b64\u65f6\u53ef\u7528?:\u653e\u5728\u7b2c\u4e00\u4e2a\u9009\u9879\u524d\u6765\u6d88\u9664\u8fd9\u79cd\u526f\u4f5c\u7528\u3002
3.7 \u540e\u5411\u5f15\u7528<\/p>
\u3000\u3000 \r\n\u5bf9\u4e00\u4e2a\u6b63\u5219\u8868\u8fbe\u5f0f\u6a21\u5f0f\u6216\u90e8\u5206\u6a21\u5f0f\u4e24\u8fb9\u6dfb\u52a0\u5706\u62ec\u53f7\u5c06\u5bfc\u81f4\u76f8\u5173\u5339\u914d\u5b58\u50a8\u5230\u4e00\u4e2a\u4e34\u65f6\u7f13\u51b2\u533a\u4e2d\uff0c\u6240\u6355\u83b7\u7684\u6bcf\u4e2a\u5b50\u5339\u914d\u90fd\u6309\u7167\u5728\u6b63\u5219\u8868\u8fbe\u5f0f\u6a21\u5f0f\u4e2d\u4ece\u5de6\u81f3\u53f3\u6240\u9047\u5230\u7684\u5185\u5bb9\r\n\u5b58\u50a8\u3002\u5b58\u50a8\u5b50\u5339\u914d\u7684\u7f13\u51b2\u533a\u7f16\u53f7\u4ece 1 \u5f00\u59cb\uff0c\u8fde\u7eed\u7f16\u53f7\u76f4\u81f3\u6700\u5927 99 \u4e2a\u5b50\u8868\u8fbe\u5f0f\u3002\u6bcf\u4e2a\u7f13\u51b2\u533a\u90fd\u53ef\u4ee5\u4f7f\u7528 '\\n' \u8bbf\u95ee\uff0c\u5176\u4e2d n \r\n\u4e3a\u4e00\u4e2a\u6807\u8bc6\u7279\u5b9a\u7f13\u51b2\u533a\u7684\u4e00\u4f4d\u6216\u4e24\u4f4d\u5341\u8fdb\u5236\u6570\u3002
<\/p>"}