Jun 24, 2020 ... def is_correct(table,number): for i in range(1,11): if table[i-1]!=i * number: return i-1.May 9, 2023 · Remove an item from a list in Python (clear, pop, remove, del) Convert pandas.DataFrame, Series and list to each other; How to start enumerate() at 1 in Python; Convert a list of strings and a list of numbers to each other in Python; zip() in Python: Get elements from multiple lists; Convert 1D array to 2D array in Python (numpy.ndarray, list)1 day ago · Changed in version 3.5: The use of venv is now recommended for creating virtual environments. Deprecated since version 3.6: pyvenv was the recommended tool for creating virtual environments for Python 3.3 and 3.4, and is deprecated in Python 3.6. On Windows, invoke the venv command as follows: c:\>Python35\python -m venv c:\path\to\myenv.Mar 19, 2024 · Python For Loop with a step size. This code uses a for loop in conjunction with the range () function to generate a sequence of numbers starting from 0, up to (but not including) 10, and with a step size of 2. For each number in the sequence, the loop prints its value using the print () function. The output will show the numbers 0, 2, 4, 6, and 8.Python 位运算符. 如果两个位均为 1，则将每个位设为 1。. 如果两位中的一位为 1，则将每个位设为 1。. 如果两个位中只有一位为 1，则将每个位设为 1。. 反转所有位。. 通过从右侧推入零来向左移动，推掉最左边的位。. 通过从左侧推入最左边的位的副本向右移动 ...Jul 25, 2023 ... Web Dev Roadmap for Beginners (Free!): https://bit.ly/DaveGrayWebDevRoadmap This Python Full Course for Beginners is an all-in-one beginner ...May 9, 2023 · Power Function in Python with Modulus. We can pass more than two parameters to the pow () in Python. The first parameter is the number on which we want to apply the Pow () function, the second parameter is the power and the third parameter is to perform the modulus operation. It return the value of 3 to the power of 4, modulus 10 (same as (3 ...Sep 19, 2018 · So, if you wanted the last element in array, you would call array[-1]. All your return c.most_common()[-1] statement does is call c.most_common and return the last value in the resulting list, which would give you the least common item in that list. Essentially, this line is equivalent to: temp = c.most_common() return temp[len(temp) - 1] Complex number literals in Python mimic the mathematical notation, which is also known as the standard form, the algebraic form, or sometimes the canonical form, of a complex number.In Python, you can use either lowercase j or uppercase J in those literals.. If you learned about complex numbers in math class, you might have seen them expressed …May 25, 2023 · The Python Modulo Operator. Basically, the Python modulo operation is used to get the remainder of a division. The modulo operator ( %) is considered an arithmetic operation, along with +, –, /, *, **, //. In most languages, both operands of this modulo operator have to be an integer. But Python Modulo is versatile in this case. 1 day ago · The decimal module provides support for fast correctly rounded decimal floating point arithmetic. It offers several advantages over the float datatype: Decimal “is based on a floating-point model which was designed with people in mind, and necessarily has a paramount guiding principle – computers must provide an arithmetic that works in the same way as the arithmetic …Nov 21, 2023 · Complexities for Removing elements in the Arrays. Time Complexity: O(1)/O(n) ( O(1) – for removing elements at the end of the array, O(n) – for removing elements at the beginning of the array and to the full array Auxiliary Space: O(1) Slicing of an Array. In Python array, there are multiple ways to print the whole array with all the …5 days ago · Install Python from python.org, Homebrew, or your Linux package manager. Use Poetry as the most well-maintained tool that provides a dependency resolver and environment management capabilities in a similar fashion as conda does. Python package management# Managing packages is a challenging problem, and, as a result, there are …Python is a versatile programming language that is widely used for its simplicity and readability. Whether you are a beginner or an experienced developer, mini projects in Python c...May 9, 2019 · 深入理解Python中的None. Python中的None是一个经常被用到的知识点，但是很多人对于None的内涵把握的还是不够精确，今天就和我一起好好理解下这个小知识点吧。. 1.None表示空，但它不等于空字符串、空列表，也不等同于False，通过下面的代码进行验证。. 2.在写代码 ...Mappings. If the primary is a mapping, the expression list must evaluate to an object whose value is one of the keys of the mapping, and the ...Jun 26, 2023 · In Python, the “//” operator works as a floor division for integer and float arguments. However, the division operator ‘/’ returns always a float value. Note: The “//” operator is used to return the closest integer value which is less than or equal to a specified expression or value. So from the above code, 5//2 returns 2.Mar 13, 2024 · 1. Operator precedence Table in Python: f (args…) {key: value…} When we have more than one operator, the one with higher precedence will be evaluated first. From the above table, we can see that parentheses will be evaluated first and lambda at the last. 2.python -c "import numpy, sys; sys.exit(numpy.test() is False)" Code of Conduct. NumPy is a community-driven open source project developed by a diverse group of contributors. The NumPy leadership has made a strong commitment to creating an open, inclusive, and positive community.1 day ago · Definition and Usage. The None keyword is used to define a null value, or no value at all. None is not the same as 0, False, or an empty string. None is a data type of its own (NoneType) and only None can be None.Python’s eval() allows you to evaluate arbitrary Python expressions from a string-based or compiled-code-based input. This function can be handy when you’re trying to dynamically evaluate Python expressions from any input that comes as a string or a compiled code object.. Although Python’s eval() is an incredibly useful tool, the function has some …Python uses the keyword None to define null objects and variables. While None does serve some of the same purposes as null in other languages, it’s another beast entirely. As the null in Python, None is not defined to be 0 or any other value. In Python, None is an object and a first-class citizen! In this tutorial, you’ll learn:Jun 9, 2020 ... https://neetcode.io/ - A better way to prepare for Coding Interviews LinkedIn: https://www.linkedin.com/in/navdeep-singh-3aaa14161/ ...Python is a popular programming language known for its simplicity and versatility. Whether you’re a seasoned developer or just starting out, understanding the basics of Python is e... Python Identity Operators. Identity operators are used to compare the objects, not if they are equal, but if they are actually the same object, with the same memory location: Operator. Description. Example. Try it. is. Returns True if both variables are the same object. x is y. Python 位运算符. 如果两个位均为 1，则将每个位设为 1。. 如果两位中的一位为 1，则将每个位设为 1。. 如果两个位中只有一位为 1，则将每个位设为 1。. 反转所有位。. 通过从右侧推入零来向左移动，推掉最左边的位。. 通过从左侧推入最左边的位的副本向右移动 ... 4. Right Triangle Star Pattern In Python * ** *** **** ***** The right triangle star pattern is a star pattern in the shape of a triangle as shown above. It is similar to the left triangle star pattern but you will have to deal with spaces. Nov 7, 2023 · Matplotlib: Visualization with Python. Matplotlib is a comprehensive library for creating static, animated, and interactive visualizations in Python. Matplotlib makes easy things easy and hard things possible. Create publication quality plots . Make interactive figures that can zoom, pan, update. Customize visual style and layout .3 days ago · This effectively limits pure Python recursion to what’s safe for the C stack. In 3.11, when CPython detects Python code calling another Python function, it sets up a new frame, and “jumps” to the new code inside the new frame. This avoids calling the C interpreting function altogether.Jan 3, 2017 · Therefore, a[:-1:-1] means "go from the end of a, which is a[-1] (since i is unspecified and k is negative), to the last element of a (since j == -1), with step size of -1". i and j are equal – you start and stop slicing in the same place – so the expression evaluates to an empty list. Sep 16, 2020 ... Learn Python basics in 1 hour! ⚡ This beginner-friendly tutorial will get you coding fast. Want to dive deeper? - Check out my Python ...Aug 20, 2023 · Python dictionary is an unordered collection of data that stores data in the format of key:value pair. It is like hash tables in any other language with the time complexity of O(1). Indexing of Python Dictionary is done with the help of keys. These are of any hashable type i.e. an object whose can never change like strings, numbers, tuples, etc.Feb 27, 2013 ... For example, maybe you want to plot column 1 vs column 2, or you want the integral of data between x = 4 and x = 6, but your vector covers 0 < x ... Python follows a convention known as the off-side rule, a term coined by British computer scientist Peter J. Landin. (The term is taken from the offside law in association football.) Languages that adhere to the off-side rule define blocks by indentation. Python is one of a relatively small set of off-side rule languages. The k-means clustering method is an unsupervised machine learning technique used to identify clusters of data objects in a dataset. There are many different types of clustering methods, but k-means is one of the oldest and most …Jan 25, 2024 · This scaling is omitted if cov='unscaled', as is relevant for the case that the weights are w = 1/sigma, with sigma known to be a reliable estimate of the uncertainty. Returns: p ndarray, shape (deg + 1,) or (deg + 1, K) Polynomial coefficients, highest power first. If y was 2-D, the coefficients for k-th data set are in p[:,k].In this tutorial, you’ll learn how to: Create integers and floating-point numbers. Round numbers to a given number of decimal places. Format and display numbers in strings. Let’s get started! Note: This tutorial is …Dec 10, 2021 · 知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。知乎凭借认真、专业、友善的社区氛围、独特的产品机制以及结构化和易获得的优质内容，聚集了中文互联网科技、商业、影视 ...Python is one of the most popular programming languages in today’s digital age. Known for its simplicity and readability, Python is an excellent language for beginners who are just...1 day ago · Python 3.12 有什么新变化？ 或自从 Python 2.0，全部的“新变化”文档 教程 开始 Python 的语法和特性之旅 库参考 标准库与内置对象 语言参考 语法与语言元素 Python 安装与使用 各种操作系统的介绍都有 Python 指南 深入学习特定主题 安装 Python 模块 第三方模块与 PyPI.org ...1 day ago · csv. writer (csvfile, dialect = 'excel', ** fmtparams) ¶ Return a writer object responsible for converting the user’s data into delimited strings on the given file-like object. csvfile can be any object with a write() method. If csvfile is a file object, it should be opened with newline='' [1].An optional dialect parameter can be given which is used to define a …Python 位运算符. 如果两个位均为 1，则将每个位设为 1。. 如果两位中的一位为 1，则将每个位设为 1。. 如果两个位中只有一位为 1，则将每个位设为 1。. 反转所有位。. 通过从右侧推入零来向左移动，推掉最左边的位。. 通过从左侧推入最左边的位的副本向右移动 ... 1. In python and other languages like C, "=" is a assignment operator and is used to assign a value to a variable. Example: a=2 # the value of a is 2. whereas "==" is Comparison operator and is used to check whether 2 expressions give the same value .Equality check returns true if it succeeds and else return false. Example: a=2 b=3 c=2. Mar 19, 2024 · Python For Loop with a step size. This code uses a for loop in conjunction with the range () function to generate a sequence of numbers starting from 0, up to (but not including) 10, and with a step size of 2. For each number in the sequence, the loop prints its value using the print () function. The output will show the numbers 0, 2, 4, 6, and 8. Mar 27, 2023 · To create a list of numbers from 1 to N in Python using the range () function you have to pass two arguments to range (): “start” equal to 1 and “stop” equal to N+1. Use the list () function to convert the output of the range () function into a list and obtain numbers in the specified range. The Bitwise complement operator (~) is a unary operator. First it converts the given decimal number to its corresponding binary value.That is in case of 2 it first convert 2 to 0000 0010 (to 8 bit binary number). Then it converts all the 1 in the number to 0,and all the zeros to 1;then the number will become 1111 1101. Mar 3, 2022 · Output: x is equal to y. Python first checks if the condition x < y is met. It isn't, so it goes on to the second condition, which in Python, we write as elif, which is short for else if. If the first condition isn't met, check the second condition, and if it’s met, execute the expression. Else, do something else. Mar 19, 2024 · Python For Loop with a step size. This code uses a for loop in conjunction with the range () function to generate a sequence of numbers starting from 0, up to (but not including) 10, and with a step size of 2. For each number in the sequence, the loop prints its value using the print () function. The output will show the numbers 0, 2, 4, 6, and 8. PCPP1™ certification is a professional high-stakes credential, an interim step to the PCPP2™ certification, and the means to demonstrate high-level Python ...Python is one of the most popular programming languages in the world. It is known for its simplicity and readability, making it an excellent choice for beginners who are eager to l...Oct 19, 2021 · Python OR Operator – Short Circuit. The Python Or operator always evaluates the expression until it finds a True and as soon it Found a True then the rest of the expression is not checked. Consider the below example for better understanding.1 day ago · 7.1.1. Formatted String Literals¶ Formatted string literals (also called f-strings for short) let you include the value of Python expressions inside a string by prefixing the string with f or F and writing expressions as {expression}. An optional format specifier can follow the expression. This allows greater control over how the value is ...Are you a Python developer tired of the hassle of setting up and maintaining a local development environment? Look no further. In this article, we will explore the benefits of swit...3 days ago · 文章浏览阅读3次。可以用循环和判断语句来实现： ```python sum = 0 for i in range(1, 101): if i % 2 == 0: # 判断是否为偶数 本硬件系统设计的目的是利用单片机技术， …Feb 19, 2020 ... 1. The built-in method: range() ... The built-in method range([start, ]stop, [step]) was my first introduction to generating sequences in Python.Mar 19, 2024 · Python Arithmetic operators are used to perform basic mathematical operations like addition, subtraction, multiplication, and division. In Python 3.x the result of division is a floating-point while in Python 2.x division of 2 integers was an integer. Mar 15, 2024 · Classification: Python is a high-level object-oriented scripting language. Usage: Back-end web developers use Python to create web applications, analyze data, …Dec 27, 2023 · In Python, Logical operators are used on conditional statements (either True or False). They perform Logical AND, Logical OR, and Logical NOT operations. OPERATOR. DESCRIPTION. SYNTAX. Example. and. Returns True if both the operands are true. x and y. Dec 8, 2022 · The default is 1. Let's see some examples that cover different ways in which arrays can be sliced. How to slice without a start or end index.In this tutorial, you’ll learn how to: Create integers and floating-point numbers. Round numbers to a given number of decimal places. Format and display numbers in strings. Let’s get started! Note: This tutorial is …Home. Python. 1 Python: What is in 1 in Python? / Python / By Varun Saharawat. 1 Python represents an integer value. Integers are whole numbers that can be positive, negative, … Python. if index % modulus == 0: print() This code takes the current iteration index and, using the modulo operator, compares it with modulus. If the result equals 0, then it can run interval-specific code. In this case, the function calls print () to add a newline, which starts a new row. Aug 5, 2022 · action-2 case pattern-3: action-3 case _: action-default. Note that the underscore symbol is what you use to define a default case for the switch statement in Python. An example of a switch statement written with the match case syntax is shown below. It is a program that prints what you can become when you learn various …Oct 10, 2023 · Its default value is 1. To understand this utility a little better, let’s look at some examples. Note that in Python, -1 represents the last index. And, while indexing or …Python list 包含任何类型的元素，并且可以包含混合类型的元素。. 以下代码中使用的 MATLAB double 函数假设 Python list 的所有元素均为数值。. 假设您有一个 Python 函 …Defining a Dictionary. Dictionaries are Python’s implementation of a data structure that is more generally known as an associative array. A dictionary consists of a collection of key-value pairs. Each key-value pair maps the key to its associated value. You can define a dictionary by enclosing a comma-separated list of key-value pairs in ...Apr 23, 2021 · Python 是一种解释型面向对象的语言Python的语法和动态类型，以及解释性语言的本质，使它成为多数平台上写脚本和快速开发应用的编程语言单引号定义法：双引号定义法：三引号定义法：其中，单引号定义法，可以内含双引号；双引号定义法，可以内含单引号；并且可以使用转义字符（\）来将引号 ...Sep 10, 2019 · 2 Answers. [:, :] literally means [all rows, all columns]. Indexing in python starts from 0 when you go from the first element to the last, but it starts from -1 when you start from the last element. So, when you do [:, -1] it means you are taking all the rows and only the last column. -1 represents the last column. Jul 25, 2023 ... Web Dev Roadmap for Beginners (Free!): https://bit.ly/DaveGrayWebDevRoadmap This Python Full Course for Beginners is an all-in-one beginner ...Python’s eval() allows you to evaluate arbitrary Python expressions from a string-based or compiled-code-based input. This function can be handy when you’re trying to dynamically evaluate Python expressions from any input that comes as a string or a compiled code object.. Although Python’s eval() is an incredibly useful tool, the function has some …Jun 26, 2023 · In Python, the “//” operator works as a floor division for integer and float arguments. However, the division operator ‘/’ returns always a float value. Note: The “//” operator is used to return the closest integer value which is less than or equal to a specified expression or value. So from the above code, 5//2 returns 2.Mappings. If the primary is a mapping, the expression list must evaluate to an object whose value is one of the keys of the mapping, and the ...May 9, 2023 · Remove an item from a list in Python (clear, pop, remove, del) Convert pandas.DataFrame, Series and list to each other; How to start enumerate() at 1 in Python; Convert a list of strings and a list of numbers to each other in Python; zip() in Python: Get elements from multiple lists; Convert 1D array to 2D array in Python (numpy.ndarray, list)1 day ago · Tutorial. This page contains the API reference information. For a more gentle introduction to Python command-line parsing, have a look at the argparse tutorial. The argparse module makes it easy to write user-friendly command-line interfaces. The program defines what arguments it requires, and argparse will figure out how to parse those out …Dec 10, 2021 · 知乎，中文互联网高质量的问答社区和创作者聚集的原创内容平台，于 2011 年 1 月正式上线，以「让人们更好的分享知识、经验和见解，找到自己的解答」为品牌使命。知乎凭借认真、专业、友善的社区氛围、独特的产品机制以及结构化和易获得的优质内容，聚集了中文互联网科技、商业、影视 ...Aug 20, 2023 · Python dictionary is an unordered collection of data that stores data in the format of key:value pair. It is like hash tables in any other language with the time complexity of O(1). Indexing of Python Dictionary is done with the help of keys. These are of any hashable type i.e. an object whose can never change like strings, numbers, tuples, etc.Python uses the keyword None to define null objects and variables. While None does serve some of the same purposes as null in other languages, it’s another beast entirely. As the null in Python, None is not defined to be 0 or any other value. In Python, None is an object and a first-class citizen! In this tutorial, you’ll learn: 1. In python and other languages like C, "=" is a assignment operator and is used to assign a value to a variable. Example: a=2 # the value of a is 2. whereas "==" is Comparison operator and is used to check whether 2 expressions give the same value .Equality check returns true if it succeeds and else return false. Example: a=2 b=3 c=2. The Bitwise complement operator (~) is a unary operator. First it converts the given decimal number to its corresponding binary value.That is in case of 2 it first convert 2 to 0000 0010 (to 8 bit binary number). Then it converts all the 1 in the number to 0,and all the zeros to 1;then the number will become 1111 1101. File "<ipython-input-6-a1fcabcd869c>", line 1 print "Hello, World!" ^ SyntaxError: Missing parentheses in call to 'print'. Did you mean print(&quo...Nov 1, 2021 · In the code mentioned above, we initialized two variables S1 and S2 with initial values as “Welcome to ” and ”AskPython” respectively. We then add the two strings using the ‘+=’ operator which will concatenate the values of the string. The output of the code is as follows: First String : Welcome to. Second String: AskPython. Jan 12, 2024 · in 在python中的使用很常见，用处也很多，很强大，这里记录下几种常见的用法。 在 for 循环中，获取列表或者元组的每一项： for item in list: 判断左边的元素是否包 …Aug 20, 2023 · Python dictionary is an unordered collection of data that stores data in the format of key:value pair. It is like hash tables in any other language with the time complexity of O(1). Indexing of Python Dictionary is done with the help of keys. These are of any hashable type i.e. an object whose can never change like strings, numbers, tuples, etc. Python follows a convention known as the off-side rule, a term coined by British computer scientist Peter J. Landin. (The term is taken from the offside law in association football.) Languages that adhere to the off-side rule define blocks by indentation. Python is one of a relatively small set of off-side rule languages. Definite iteration loops are frequently referred to as for loops because for is the keyword that is used to introduce them in nearly all programming languages, including Python. Historically, programming languages have offered a few assorted flavors of for loop. These are briefly described in the following sections. Remove ads. Modern society is built on the use of computers, and programming languages are what make any computer tick. One such language is Python. It’s a high-level, open-source and general-...Modern society is built on the use of computers, and programming languages are what make any computer tick. One such language is Python. It’s a high-level, open-source and general-...
Dec 11, 2023 · In Python, we can achieve incrementing by using Python ‘+=’ operator. This operator adds the value on the right to the variable on the left and assigns the result to …. Bet jack
The k-means clustering method is an unsupervised machine learning technique used to identify clusters of data objects in a dataset. There are many different types of clustering methods, but k-means is one of the oldest and most …Python 3.8.1 - Dec. 18, 2019. Note that Python 3.8.1 cannot be used on Windows XP or earlier. Download Windows help file; Download Windows x86 embeddable zip file; Download Windows x86 executable installer; Download Windows x86 web-based installer; Download Windows x86-64 embeddable zip file; Download Windows x86-64 executable …Mar 17, 2023 · Numpy支持大量的维度数组和矩阵运算，对数组运算提供了大量的数学函数库！Numpy比Python列表更具优势，其中一个优势便是速度。在对大型数组执行操作时，Numpy的速度比Python列表的速度快了好几百。因为Numpy数组本身能节省内存，并且Numpy在执行算术、统计和线性代数运算时采用了优化算法。Jul 21, 2022 · Kolade Chris. In Python, you use the double slash // operator to perform floor division. This // operator divides the first number by the second number and rounds the result down to the nearest integer (or whole number). In this article, I will show you how to use the // operator and compare it to regular division so you can see how it works.Oct 19, 2021 · Python OR Operator – Short Circuit. The Python Or operator always evaluates the expression until it finds a True and as soon it Found a True then the rest of the expression is not checked. Consider the below example for better understanding.Python is a popular programming language known for its simplicity and versatility. Whether you’re a seasoned developer or just starting out, understanding the basics of Python is e...Sep 16, 2020 ... Learn Python basics in 1 hour! ⚡ This beginner-friendly tutorial will get you coding fast. Want to dive deeper? - Check out my Python ...5 days ago · Machine Learning in Python Getting Started Release Highlights for 1.4 GitHub. Simple and efficient tools for predictive data analysis; Accessible to everybody, and reusable in various contexts ... February 2024. scikit-learn 1.4.1.post1 is available for download . January 2024. scikit-learn 1.4.0 is available for download . October 2023. ...Jan 25, 2024 · This scaling is omitted if cov='unscaled', as is relevant for the case that the weights are w = 1/sigma, with sigma known to be a reliable estimate of the uncertainty. Returns: p ndarray, shape (deg + 1,) or (deg + 1, K) Polynomial coefficients, highest power first. If y was 2-D, the coefficients for k-th data set are in p[:,k].Python 位运算符. 如果两个位均为 1，则将每个位设为 1。. 如果两位中的一位为 1，则将每个位设为 1。. 如果两个位中只有一位为 1，则将每个位设为 1。. 反转所有位。. 通过从右侧推入零来向左移动，推掉最左边的位。. 通过从左侧推入最左边的位的副本向右移动 ...Python 位运算符. 如果两个位均为 1，则将每个位设为 1。. 如果两位中的一位为 1，则将每个位设为 1。. 如果两个位中只有一位为 1，则将每个位设为 1。. 反转所有位。. 通过从右侧推入零来向左移动，推掉最左边的位。. 通过从左侧推入最左边的位的副本向右移动 ...May 9, 2023 · Remove an item from a list in Python (clear, pop, remove, del) Convert pandas.DataFrame, Series and list to each other; How to start enumerate() at 1 in Python; Convert a list of strings and a list of numbers to each other in Python; zip() in Python: Get elements from multiple lists; Convert 1D array to 2D array in Python (numpy.ndarray, list)... Python library modules described in The Python Standard Library. The Glossary is also worth going through. 1. Whetting Your Appetite · 2. Using the Python ...Mar 19, 2024 · Python Arithmetic operators are used to perform basic mathematical operations like addition, subtraction, multiplication, and division. In Python 3.x the result of division is a floating-point while in Python 2.x division of 2 integers was an integer. Python 3.12.1. Release Date: Dec. 8, 2023 This is the first maintenance release of Python 3.12. Python 3.12 is the newest major release of the Python programming language, and it contains many new features and optimizations. 3.12.1 is the latest maintenance release, containing more than 400 bugfixes, build improvements and documentation changes …Mar 4, 2024 · Note. The Python and NumPy indexing operators [] and attribute operator . provide quick and easy access to pandas data structures across a wide range of use cases. This makes interactive work intuitive, as there’s little new to learn if you already know how to deal with Python dictionaries and NumPy arrays.Aug 27, 2023 ... In the above snippet, my_list.index('banana') returns '1', which is the index of 'banana' in the list my_list . Python list indices start f...In Python, [::-1] means reversing a string, list, or any iterable with an ordering. For example: hello = "Hello world" nums = [1, 2, 3, 4] print(hello[::-1]) print(nums[::-1]) Output: dlrow olleH. [4, 3, 2, 1] This is the quick answer. See more... Python library modules described in The Python Standard Library. The Glossary is also worth going through. 1. Whetting Your Appetite · 2. Using the Python ...Aug 10, 2010 · s = slice(1, 2, 3) assert s.start == 1 assert s.stop == 2 assert s.step == 3 This is notably used in Numpy to slice multi-dimensional arrays in any direction. Of course, any sane API should use ::3 with the usual "every 3" semantic. The related Ellipsis is covered further at: What does the Ellipsis object do? .