# coding=utf8
# the above tag defines encoding for this document and is for Python 2.x compatibility
import re
regex = r"""
(?: # 采用非捕获括号进行分组（非必要不使用捕获型括号）
(`{3,}) # 捕获组，匹配三个及以上反引号，并进行捕获
[\s\S]*? # 采用非贪婪匹配（必须），匹配0到n次空白或非空白字符（任意字符）
(?:(?:\1`*)|\Z) # 引用，引用了之前的捕获组，若之前捕获了5个反引号，则在此必须匹配5个以上反引号，若开头三个以上反引号，后面没有比开头更多的反引号，则后面都是代码块
) # 结束第一个分支
| # 或符号
(?: # 同上，采用非捕获型括号
(~{3,}) # 同上，匹配三个及以上波浪号并进行捕获
[\s\S]*? # 同上，非贪婪匹配来匹配0到n次空白或非空白字符
(?:(?:\2~*)|\Z) # 引用，引用了之前的捕获组
) # 结束第二个分支
| # 或符号
(?: # 同上，采用非捕获型括号
(?<= # 肯定型逆序环视，左侧文本必须满足条件才可以匹配
(?:^\n)|(?:^\A) # 上一行必须只有一个回车（以回车符号开头）或没有上一行
) # 结束环视
(?: # 采用非捕获型括号分组
(?:\s{4,}?|\t+?)[^\n]*(?:\n|$) # 匹配四个及以上空格或一个以上制表符开启的一行
)+ # 上面的子组匹配1次到n次
) # 结束第三个分支
"""
test_str = (" this is a code block\n"
" \n"
"// 1. 匹配四个空格导出的代码块\n\n"
" functino(asfd)\n"
" safdsadf\n"
" safsadf\n"
" safdsdaf\n"
" \n\n\n"
"// 2. 匹配三个反引号所引出的代码块\n"
"```\n"
" func function(){\n"
" }\n"
"```\n\n"
"这里是一些文本\n"
"……\n"
"………………\n\n"
"``` python\n"
" print(\"hello\")\n"
"```\n\n"
"// 3.如果四个空格之前的一行不是回车独占一行，则不会导出代码块（符合Markdown约定）\n"
" function(asfd)\n"
" safdsadf\n"
" safsadf\n"
" safdsdaf\n"
" safd\n"
" \n\n"
"// 4. 匹配三个波浪号导出的代码块\n\n"
"~~~\n"
" fmt.println(123)\n"
"~~~\n\n"
"// 5. 匹配前后四个及以上反引号导出的代码块\n"
"````\n"
"aaa\n"
"```\n"
"````\n\n"
"这里是一些文本……\n\n"
"`````\n"
" print(\"this is a code block\")\n"
"`````\n\n"
"`````\n"
" print(\"this is a code block\")\n"
"````````````````````````\n"
"// 6. 匹配前后四个及以上波浪号导出的代码块\n"
"~~~~\n"
"aaa\n"
"~~~\n"
"~~~~\n\n"
"这里是一些文本……\n\n"
"~~~~~~\n"
" print(\"this is a code block\")\n"
"~~~~~~\n\n"
"~~~~~~\n"
" print(\"this is a code block\")\n"
"~~~~~~~~~~~~~~~~~~~~~~~~\n\n"
"// 7. 只有开头，没有结尾的，都算代码块\n"
"```\n"
"asdfasdf\n"
"asdfasdf\n"
"asdfasdf\n"
"asdfasdf\n"
"asdfasdf\n"
"asdf\n"
"没有结尾，这里也算代码块")
subst = ""
# You can manually specify the number of replacements by changing the 4th argument
result = re.sub(regex, subst, test_str, 0, re.VERBOSE | re.MULTILINE)
if result:
print (result)
# Note: for Python 2.7 compatibility, use ur"" to prefix the regex and u"" to prefix the test string and substitution.
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html