Python 正则表达式：入门指南和示例

import\s+re\n\n#\s+Example\s+1:\s+Matching\s+a\s+pattern\s+in\s+a\s+string\nstring\s+=\s"Hello,\s+my\s+name\s+is\s+John\s+Doe.\s+I\s+am\s+25\s+years\s+old."
pattern\s+=\s"John\s+Doe"
result\s+=\sre.search(pattern,\s+string)\nif\s+result:\n\tprint("Pattern\s+found.")
else:\n\tprint("Pattern\s+not\s+found.")
\n#\s+Example\s+2:\s+Extracting\s+information\s+from\s+a\s+string\nstring\s+=\s"I\s+have\s+3\s+cats\s+and\s+2\s+dogs."
pattern\s+=\s"\d+"
result\s+=\sre.findall(pattern,\s+string)\nif\s+result:\n\tprint(f"Number(s)\s+found:\s+{',\s+'.join(result)}")
else:\n\tprint("No\s+numbers\s+found.")
\n#\s+Example\s+3:\s+Replacing\s+a\s+pattern\s+in\s+a\s+string\nstring\s+=\s"I\s+love\s+cats,\s+but\s+I\s+hate\s+dogs."
pattern\s+=\s"cats"
replacement\s+=\s"dogs"
result\s+=\sre.sub(pattern,\s+replacement,\s+string)\nprint(result)