How to change all variable names in python
Use the Rename refactoring to change names of symbols, files, and all the references to them throughout code. Renaming local variables or private methods can be done easily inline since only the limited scope is affected. Renaming classes or public methods could potentially impact a lot of files. Preview potential changes before you refactor. In the editor start renaming a code element. PyCharm will display in the gutter. Click the gutter icon or press Alt+Enter and apply a suggestion. You might be prompted to confirm changes in comments. Once you
confirm your choice, PyCharm renames the code element and updates its usages accordingly. In the editor, select an element you
want to rename. If you need to rename a file, select one in the Project tool window. Press
Shift+F6 or from the main menu, select . You can perform the
rename refactoring in-place or press
Shift+F6 again to open the Rename dialog. Enter a
new name of the element to enable the Preview and Refactor buttons. You can specify additional options. For example, specify where to search for element occurrences, or what else to rename. You can also specify a scope for the
refactoring. Click Preview to see the potential changes or click Refactor. When you click Preview, PyCharm opens the Find tool window with the results of found usages where you can check the results and confirm the refactoring (Do
Refactor). Next time you invoke the Rename refactoring, PyCharm remembers the options you have specified inside the Rename dialog. Let's rename a method:
Before After import datetime def was_published_today(self): return self.pub_date.date () == datetime.date.today() import datetime def published_today(self): return self.pub_date.date () == datetime.date.today() Last modified: 21 July 2022 You wrote a function which you use all over the place in a project. Or a class. The name no longer matches its purpose. But the change is too much of a hassle. The IDE knows where it is used. Even better, it knows the difference between usage in your project vs. finding it in a dependency, and best of all, usage as a symbol vs. just some letters in a string. What if the same symbol name is used in two Python modules? Yep, PyCharm can tell the difference and only rename to the appropriate the symbol from that module. Same for method names. Have the same method in two classes? Simply put your cursor on a symbol and use Change your mind? Refactoring is done as a single editor transaction, meaning Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Variables in Python In the previous tutorial on Basic Data Types in Python, you saw how values of various Python data types can be created. But so far, all the values shown have been literal or constant values: If you’re writing more complex code, your program will need data that can change as program execution proceeds. Here’s what you’ll learn in this tutorial: You will learn how every item of data in a Python program can be described by the abstract term object, and you’ll learn how to manipulate objects using symbolic names called variables. Variable AssignmentThink of a variable as a name attached to a particular object. In Python, variables need not be declared or defined in advance, as is the case in many other programming languages. To create a variable, you just assign it a value and then start using it. Assignment is done with a single equals sign ( This is read
or interpreted as “ Just as a literal value can be displayed directly from the interpreter prompt in a REPL session without the need for Later, if you change the value of >>>
Python also allows chained assignment, which makes it possible to assign the same value to several variables simultaneously: >>>
The chained assignment above assigns Variable Types in PythonIn many programming languages, variables are statically typed. That means a variable is initially declared to have a specific data type, and any value assigned to it during its lifetime must always have that type. Variables in Python are not subject to this restriction. In Python, a variable may be assigned a value of one type and then later re-assigned a value of a different type: >>>
Object ReferencesWhat is actually happening when you make a variable assignment? This is an important question in Python, because the answer differs somewhat from what you’d find in many other programming languages. Python is a highly object-oriented language. In fact, virtually every item of data in a Python program is an object of a specific type or class. (This point will be reiterated many times over the course of these tutorials.) Consider this code: When presented with the statement
You can see that an integer object is created using the built-in >>>
A Python variable is a symbolic name that is a reference or pointer to an object. Once an object is assigned to a variable, you can refer to the object by that name. But the data itself is still contained within the object. For example: This assignment creates an integer object with the value The following code verifies that >>>
Now consider the following statement: What happens when it is executed? Python does not create another object. It simply creates a new symbolic name or reference, Next, suppose you do this: Now Python creates a new integer object with the value Lastly, suppose this statement is executed next: Now Python creates a string object with the value There is no longer any reference to the integer object Tutorials in this series will occasionally refer to the lifetime of an object. An object’s life begins when it is created, at which time at least one reference to it is created. During an object’s lifetime, additional references to it may be created, as you saw above, and references to it may be deleted as well. An object stays alive, as it were, so long as there is at least one reference to it. When the number of references to an object drops to zero, it is no longer accessible. At that point, its lifetime is over. Python will eventually notice that it is inaccessible and reclaim the allocated memory so it can be used for something else. In computer lingo, this process is referred to as garbage collection. Object IdentityIn Python, every object that is created is given a number that uniquely identifies it. It is guaranteed that no two objects will have the same identifier during any period in which their lifetimes overlap. Once an object’s reference count drops to zero and it is garbage collected, as happened to the The built-in Python function >>>
After the assignment
Variable NamesThe
examples you have seen so far have used short, terse variable names like Officially, variable names in Python can be any length and can consist of uppercase and lowercase letters ( For example, all of the following are valid variable names: >>>
But this one is not, because a variable name can’t begin with a digit: >>>
Note that case is significant. Lowercase and uppercase letters are not the same. Use of the underscore character is significant as well. Each of the following defines a different variable: >>>
There is nothing stopping you from creating two different variables in the same program called It is worthwhile to give a variable a name that is descriptive enough to make clear what it is being used for. For example, suppose you are tallying the number of people who have graduated college. You could conceivably choose any of the following: >>>
All of them are probably better choices than On the other hand, they aren’t all necessarily equally legible. As with many things, it is a matter of personal preference, but most people would find the first two examples, where the letters are all shoved together, to be harder to read, particularly the one in all capital letters. The most commonly used methods of constructing a multi-word variable name are the last three examples:
Programmers debate hotly, with surprising fervor, which of these is preferable. Decent arguments can be made for all of them. Use whichever of the three is most visually appealing to you. Pick one and use it consistently. You will see later that variables aren’t the only things that can be given names. You can also name functions, classes, modules, and so on. The rules that apply to variable names also apply to identifiers, the more general term for names given to program objects. The Style Guide for Python Code, also known as PEP 8, contains Naming Conventions that list suggested standards for names of different object types. PEP 8 includes the following recommendations:
Reserved Words (Keywords)There is one more restriction on identifier names. The Python language reserves a small set of keywords that designate special language functionality. No object can have the same name as a reserved word. In Python 3.6, there are 33 reserved keywords:
You can see this list any time by typing Trying to create a variable with the same name as any reserved word results in an error: >>>
ConclusionThis tutorial covered the basics of Python variables, including object references and identity, and naming of Python identifiers. You now have a good understanding of some of Python’s data types and know how to create variables that reference objects of those types. Next, you will see how to combine data objects into expressions involving various operations. Watch Now This tutorial has a related video course created by the Real Python team. Watch it together with the written tutorial to deepen your understanding: Variables in Python How do you change a variable name everywhere?Use instead Ctrl+Shift+L to select all occurrence. Once you selected the occurrences you can edit them by just typing the new name.
How do I change all variables at once?Direct link to this answer. select the variable you want to replace.. Press control + f (this is used to find). A pop out comes, there will be a option find, replace,. replace all.. Type what you want to replace with... Go for find and replace or Replace all.. How do I change the variable name everywhere in PyCharm?Press Shift+F6 or from the main menu, select Refactor | Rename. You can perform the rename refactoring in-place or press Shift+F6 again to open the Rename dialog.
How do you dynamically change a variable name in Python?Use the for Loop to Create a Dynamic Variable Name in Python
The globals() method in Python provides the output as a dictionary of the current global symbol table. The following code uses the for loop and the globals() method to create a dynamic variable name in Python. Output: Copy Hello from variable number 5!
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