What does [:-1] mean/do in python? - Stack Overflow

Working on a python assignment and was curious as to what [:-1] means in the context of the following code: instructions = f.readline()[:-1] Have searched on here on S.O. and on Google but to no avail. Would love an explanation!

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Python Slicing – How to Slice an Array and What Does [::-1] Mean?

Here, we specify a start of index 2, no end, and a step of -1. Slicing here will start from index 2 which is 3. The negative steps mean the next value in the slice will be at an index smaller than the previous index by 1. This means 2 - 1 which is 1 so the value at this index, which is 2 will be added to the slice.

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Python increment by 1 - AskPython

In this case, the += operator merges the dictionary d with the dictionary {"c": 3}, resulting in the dictionary {“a”: 1, “b”: 2, “c”: 3}.. Overall, to increment a variable by 1 in Python, you can use the augmented assignment operator +=.This operator adds the right operand to the left operand and assigns the result to the left operand, allowing you to increment variables of ...

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Python Operators - W3Schools

W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.

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Welcome to Python.org

# Python 3: Simple arithmetic >>> 1 / 2 0.5 >>> 2 ** 3 8 >>> 17 / 3 # classic division returns a float 5.666666666666667 >>> 17 // 3 # floor division 5 Intuitive Interpretation Calculations are simple with Python, and expression syntax is straightforward: the operators + , - , * and / work as expected; parentheses () can be used for grouping.

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Python中[-1]、[:-1]、[::-1]、[n::-1]、[:,:,0]、[…,0]、[…,::-1] 的理解

1]是倒是第一列的所有元素,[1,:]是取第一行的所有元素 python数组操作中,from_num:end_num表示从[from_num,end_num)的范围,如果from_num不写,表示从0开始,如果end_num不写表示到最后一个。

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Python List Slicing - GeeksforGeeks

Python list slicing is fundamental concept that let us easily access specific elements in a list. In this article, we’ll learn the syntax and how to use both positive and negative indexing for slicing with examples. Example: Get the items from a list starting at position 1 and ending at position 4 (exclusive). Python

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The Python Tutorial — Python 3.13.3 documentation

The Python interpreter is easily extended with new functions and data types implemented in C or C++ (or other languages callable from C). Python is also suitable as an extension language for customizable applications. This tutorial introduces the reader informally to the basic concepts and features of the Python language and system.

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Learn Python - Free Interactive Python Tutorial

Other Python Tutorials. DataCamp has tons of great interactive Python Tutorials covering data manipulation, data visualization, statistics, machine learning, and more; Read Python Tutorials and References course from After Hours Programming; Contributing Tutorials. Read more here: Contributing Tutorials

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Python Lists - GeeksforGeeks

In Python, a list is a built-in dynamic sized array (automatically grows and shrinks). We can store all types of items (including another list) in a list. A list may contain mixed type of items, this is possible because a list mainly stores references at contiguous locations and actual items maybe stored at different locations.

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