Trade data-driven transport mode selection

Python Code Basics: Variables and Trade data-driven transport mode selectionStrings Python is a widely used programming language, which is widely popular for its simple, easy-to-understand, easy-to-use and widely supported library. In this article, we will discuss two basic concepts in Python: variables and strings. 1. Variables are an identifier used to store values in Python. Values can be integers, floating point numbers, strings or other types of data. To create a variable, just add an equal sign before its name and assign it to the required value. For example, the following code creates a variable named "x" and sets its value to 5: x = 5 can use the variable in the code. In this example, we can use the variable "x" to represent the value "5".Print(x) # Output 5Python is a dynamic type language, which means that the type of the variable can be automatically determined according to the stored value. For example: x = 5 # integer y = 5.0 # floating point z = "Hello, World!" # Variable names in string Python are case-sensitive, so "x" and "X" represent two different variables. When assigning values to variables, Python also supports multivariable assignment operations, as follows: x, y, z = 5, 10.0, "Hello" multivariable assignment operations can be used to conveniently initialize multiple variables. When assigning values to multiple variables, the number of variables must match the number of values. Two. String PythoThe string in n is composed of a sequence of characters, which can contain letters, numbers, spaces, and other characters. The way to define a string is very simple. You just need to wrap the string in quotation marks in a certain format. For example: my_string = "Hello, World!" In the above code, we assign a variable named "my_string" as a string. Python also supports three quotation marks to define multi-line strings: my_string = ""This is amulti-line string""" Like variables, strings in Python can be dynamically modified. To access a character in a string, you can use the index. For example, to access the stringThe first character can be used with the index "0": my_string = "Hello, World!" Print(my_string[0]) # Output H string also supports slicing operations, which means that a substring can be obtained from the string. The slice is implemented using the colon operator (:), as follows: my_string = "Hello, World!" Print(my_string[0:5]) # Output Hello In the above code, use my_string[0:5] for slicing operation, and you will get a substring from index 0 to 4. Strings also support many other operations, such as character replacement, case change, etc. These operations can be implemented through Python's built-in string methods.For example: my_string = "Hello, World!" print(my_string.replace("Hello", "Hi")) # Output Hi, World! In this case, use the replace() method to replace "Hello" in the string with "Hi". Summary This article introduces two basic concepts in Python: variables and strings. The rich nature of Python makes it a programming language suitable for beginners, and it is also very suitable for building large-scale, enterprise-level applications. Before you start writing Python programs, you should make sure that you have a basic understanding of variables and strings, and learn how to use Python's built-in string methods.

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