Question
You are trying to use a regular expression to match a large block of text, and you need Match across multiple lines.
Solution
This problem typically occurs when you use dot (.) to match any character, but forget that dot (.) cannot match newlines. conforming facts. For example, suppose you want to try to match the C-delimited comment:
>>> comment = re.compile(r'/\*(.*?)\*/')<br/>>>> text1 = '/* this is a comment */'<br/>>>> text2 = '''/* this is a<br/>... multiline comment */<br/>... '''<br/>>>><br/>>>> comment.findall(text1)<br/>[' this is a comment ']<br/>>>> comment.findall(text2)<br/>[]<br/>>>><br/>
To fix this problem, you can modify the pattern string to add support for newlines. For example:
>>> comment = re.compile(r'/\*((?:.|\n)*?)\*/')<br/>>>> comment.findall(text2)<br/>[' this is a\n multiline comment ']<br/>>>><br/>
In this pattern, (?:.|\n) specifies a non-capturing group (that is, it defines a group that is only used for matching and cannot be captured or numbered individually. ).
Discussion
re.compile() The function accepts a flag parameter called re.DOTALL , which is very useful here . It allows . in regular expressions to match any character including newlines. For example:
>>> comment = re.compile(r'/\*(.*?)\*/', re.DOTALL)<br/>>>> comment.findall(text2)<br/>[' this is a\n multiline comment ']<br/>
For simple cases using re.DOTALL tag parameters work well, but if the pattern is very complex or multiple patterns are combined to construct a string token (Detailed description in Section 2.18). At this time, some problems may occur when using this mark parameter. If you have a choice, it's better to define your own regular expression pattern so that it works well without the need for additional marker parameters.
Recommended tutorial: "Python Tutorial"
The above is the detailed content of Understanding Python multi-line matching patterns. For more information, please follow other related articles on the PHP Chinese website!
Python and Time: Making the Most of Your Study TimeApr 14, 2025 am 12:02 AMTo maximize the efficiency of learning Python in a limited time, you can use Python's datetime, time, and schedule modules. 1. The datetime module is used to record and plan learning time. 2. The time module helps to set study and rest time. 3. The schedule module automatically arranges weekly learning tasks.
Python: Games, GUIs, and MoreApr 13, 2025 am 12:14 AMPython excels in gaming and GUI development. 1) Game development uses Pygame, providing drawing, audio and other functions, which are suitable for creating 2D games. 2) GUI development can choose Tkinter or PyQt. Tkinter is simple and easy to use, PyQt has rich functions and is suitable for professional development.
Python vs. C : Applications and Use Cases ComparedApr 12, 2025 am 12:01 AMPython is suitable for data science, web development and automation tasks, while C is suitable for system programming, game development and embedded systems. Python is known for its simplicity and powerful ecosystem, while C is known for its high performance and underlying control capabilities.
The 2-Hour Python Plan: A Realistic ApproachApr 11, 2025 am 12:04 AMYou can learn basic programming concepts and skills of Python within 2 hours. 1. Learn variables and data types, 2. Master control flow (conditional statements and loops), 3. Understand the definition and use of functions, 4. Quickly get started with Python programming through simple examples and code snippets.
Python: Exploring Its Primary ApplicationsApr 10, 2025 am 09:41 AMPython is widely used in the fields of web development, data science, machine learning, automation and scripting. 1) In web development, Django and Flask frameworks simplify the development process. 2) In the fields of data science and machine learning, NumPy, Pandas, Scikit-learn and TensorFlow libraries provide strong support. 3) In terms of automation and scripting, Python is suitable for tasks such as automated testing and system management.
How Much Python Can You Learn in 2 Hours?Apr 09, 2025 pm 04:33 PMYou can learn the basics of Python within two hours. 1. Learn variables and data types, 2. Master control structures such as if statements and loops, 3. Understand the definition and use of functions. These will help you start writing simple Python programs.
How to teach computer novice programming basics in project and problem-driven methods within 10 hours?Apr 02, 2025 am 07:18 AMHow to teach computer novice programming basics within 10 hours? If you only have 10 hours to teach computer novice some programming knowledge, what would you choose to teach...
How to avoid being detected by the browser when using Fiddler Everywhere for man-in-the-middle reading?Apr 02, 2025 am 07:15 AMHow to avoid being detected when using FiddlerEverywhere for man-in-the-middle readings When you use FiddlerEverywhere...
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
AI Hentai Generator
Generate AI Hentai for free.
Hot Article
Hot Tools
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.
SublimeText3 English version
Recommended: Win version, supports code prompts!
SublimeText3 Mac version
God-level code editing software (SublimeText3)
