What is the difference between append and extend in python
Look at the code first, and then explain the principle
Principle:
The two methods of Lists extend and append looks similar, but is actually completely different. extend accepts a parameter, which is always a list, and adds each element in this list to the original list.
Here there are 3 elements in the list ('a', 'b' and 'c'), and use another one with 3 elements ('d', 'e' and 'f') list is expanded so there are 6 elements in the new list.
Append, on the other hand, accepts a parameter, which can be of any data type, and is simply appended to the end of the list. Here the append method is called with a list parameter containing 3 elements.
The original list containing 3 elements now contains 4 elements. Why 4 elements? Because the last element just appended is itself a list. Lists can contain any type of data, including other lists. This may or may not be the result you want. If your intention is to extend, don't use append
The above is the detailed content of What is the difference between append and extend in python. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undress AI Tool
Undress images for free

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

ArtGPT
AI image generator for creative art from text prompts.

Stock Market GPT
AI powered investment research for smarter decisions

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Run pipinstall-rrequirements.txt to install the dependency package. It is recommended to create and activate the virtual environment first to avoid conflicts, ensure that the file path is correct and that the pip has been updated, and use options such as --no-deps or --user to adjust the installation behavior if necessary.

This tutorial details how to efficiently merge the PEFT LoRA adapter with the base model to generate a completely independent model. The article points out that it is wrong to directly use transformers.AutoModel to load the adapter and manually merge the weights, and provides the correct process to use the merge_and_unload method in the peft library. In addition, the tutorial also emphasizes the importance of dealing with word segmenters and discusses PEFT version compatibility issues and solutions.

Python is a simple and powerful testing tool in Python. After installation, test files are automatically discovered according to naming rules. Write a function starting with test_ for assertion testing, use @pytest.fixture to create reusable test data, verify exceptions through pytest.raises, supports running specified tests and multiple command line options, and improves testing efficiency.

Theargparsemoduleistherecommendedwaytohandlecommand-lineargumentsinPython,providingrobustparsing,typevalidation,helpmessages,anderrorhandling;usesys.argvforsimplecasesrequiringminimalsetup.

This article aims to explore the common problem of insufficient calculation accuracy of floating point numbers in Python and NumPy, and explains that its root cause lies in the representation limitation of standard 64-bit floating point numbers. For computing scenarios that require higher accuracy, the article will introduce and compare the usage methods, features and applicable scenarios of high-precision mathematical libraries such as mpmath, SymPy and gmpy to help readers choose the right tools to solve complex accuracy needs.

PyPDF2, pdfplumber and FPDF are the core libraries for Python to process PDF. Use PyPDF2 to perform text extraction, merging, splitting and encryption, such as reading the page through PdfReader and calling extract_text() to get content; pdfplumber is more suitable for retaining layout text extraction and table recognition, and supports extract_tables() to accurately capture table data; FPDF (recommended fpdf2) is used to generate PDF, and documents are built and output through add_page(), set_font() and cell(). When merging PDFs, PdfWriter's append() method can integrate multiple files

Import@contextmanagerfromcontextlibanddefineageneratorfunctionthatyieldsexactlyonce,wherecodebeforeyieldactsasenterandcodeafteryield(preferablyinfinally)actsas__exit__.2.Usethefunctioninawithstatement,wheretheyieldedvalueisaccessibleviaas,andthesetup

Identifyrepetitivetasksworthautomating,suchasorganizingfilesorsendingemails,focusingonthosethatoccurfrequentlyandtakesignificanttime.2.UseappropriatePythonlibrarieslikeos,shutil,glob,smtplib,requests,BeautifulSoup,andseleniumforfileoperations,email,w
