Python Thread Return Value

A thread in a program is a collection of instructions that can be carried out separately from the rest of the program. As a result, each of the numerous little tasks that an extensive program can be divided into multiple threads as long as their execution is independent of that of the other tasks. If a program only runs on one thread, it only uses one CPU or that one piece of code. However, if a program can be divided into several threads and have each of these threads use a separate CPU, the program will run much quicker and be more effective. A thread never provides a result directly in Python. The thread “start()” procedure which generates an execution thread, starts the running actions of the thread that runs our script. The “run()” approach may employ the target method if one is provided. The objective is simply to call the function in a thread a few at a time.

Example 1: Python Function Returning the Value From a Threaded Operation

In this instance, we’ll use a Python script to return the function value from the thread. A thread is a unique processing flow. This suggests that your code will handle two simultaneous occurrences. The bulk of Python solutions, however, only create the idea that multiple threads are active at the same time. The return type of a function is typically used to describe the value it provides to the user. All Python procedure seems to involve an event handler, either directly or unintentionally. A thread does not respond instantly to values. The “run()” process is termed by the thread’s start() method, creating a separate thread of processing for our code. If it is supplied, the target function might be called using the “run()” method. For retrieving values from a thread, a thread in a script must first be created. We can return a function value from a single thread or several threads.

Let’s now begin to implement the code. First, we import the thread from the threading section. The thread module must be imported to create threads in Python. The “threading” package’s entity creation considers each thread as an object. Whereas the “thread” package takes into account a thread-like function. Next, we define a function with the name “func” in the next step. Since this function is one that the user can specify, we gave it a name of our choosing. “argu1” and “returning_val” were supplied as parameters to the function “func” in its parenthesis.

Then, in the following step, we use “returning_val” and pass the value “0” while setting the phrase “Return the value from” and passing the “argu1” argument with the add symbol. Following that, we created the variable “returning_1_value” and set it to “None*1”. Similarly, we created “returning_2_value” and set it to “None*1” for the second returning value. The “func” method shows the argument 1’s value and inserts the return statement into the returning value 0 positions.

To create a thread and call the function within it, we must first call “Thread” and then “target=func” in each of its parentheses. Target is essentially a function, so we target to “func” and send the argument list from the thread, which contains “Thread 1” and the “returning 1 value”. In this case, returning 1 value is used to retrieve the value from the function where this thread is stored in the variable “thread1”.Then, we carry out the same procedure for the second thread. We call threads, and within it, we pass the function “func,” the parameter list for which is “Thread 2”, as well as the “returning_2_value,” which we use to obtain the function’s value. This thread stores it in the variable “thread2”. The threads are now started using the “start()” function with “thread1” and “thread2”. In the following step, we utilize the “join()” methods to wait for the threads to finish executing. The “print()” function is then used in the following line with the arguments “returnin_1_value” and “returning_2_value”.

In the output, it displayed the return value. First, it showed the print statement in which we passed the returning value. The value for 1 is “Thread1”, and 2 is “Thread 2”. Then it displayed the threads statement, which is “Return the value from Thread 1”, and the second is “Return the value from Thread 2”.

Example 2: Multiple Values Getting Returns From a Thread

In this instance, we’ll return multiple values from the threads to the output display. When a program produces numerous threads and cycles through their execution, it is multithreading, also known as threading, since it prevents one longer-running operation from blocking all the others. This is effective for activities that can be divided into smaller subtasks, each of which can be given to a thread for execution.

Let’s begin implementing the code by importing three libraries. The Python time package provides a variety of coding representations for time, such as objects, numbers, and characters. In the first import, we import “sleep” from the time module. It also allows you to evaluate the effectiveness of your script and wait while it runs, in addition to other features than time representation. The time module’s sleep() procedure lets you suspend the execution of the calling thread for whatever many seconds you like. After that, we import “Thread” from the threading module. The class “CustomThread” is defined in the following step, and it accepts the argument “Thread” as its only parameter.

Next, we define the “_init_” method and supply the keyword “self” to it. Each object or class in Python has the “self” keyword assigned to it. The “self” keyword allows one to rapidly access all examples declared within a class, including its methods and attributes. One of Python’s restricted methods is __init__. In the following line, we call this method using a Thread by using “Thread. init (self)”. Then, in the following line, we define the “run()” function and pass the argument “self.” Then, we use the “sleep()” method and set the time to “1” seconds which means it halts its execution for one second.

Then, we set the values in each instance variable using “self.val1”, “self.val2”, and “self.val3” setting their values to “Hello”, “18”, and “True”, respectively. In other words, we called the values by passing the keyword “self” here. Next, we called the “CustomThread” in the thread and saved it in the “thread” variable. After that, we use the start() method with threads to start the thread and the “join()” technique with “thread” to wait for the main program to run. Next, we call the “print()” function, and inside of it, we call the thread return values passing the arguments “thread.val1”, “thread.val2”, and “thread.val3”.

As shown in the following screenshot, it returns multiple values from threads in the output. The first value is “Hello,” the second is “18,” and the third is “True,” which are thread values that we had stored in the “run()” function.


We discussed how to simply return the thread value or the values of a function from a thread in this article. Two instances were used in this article. The thread operation’s function value was returned in the first, and the numerous thread values were returned in the output display of the second. In each of our instances, we’ve defined user-defined functions that are called in threads. The “CustomThread” class was also defined in the second example. You will benefit from reading this article when researching this topic.

About the author

Aqsa Yasin

I am a self-motivated information technology professional with a passion for writing. I am a technical writer and love to write for all Linux flavors and Windows.