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1. Top results related to python define function

   • Python define function inside if block or vice versa

     Top Answer

     Answered Jul 14, 2017 · 3 votes

     Depends on what you want to use it for. They can both be used in useful ways. Compare the two examples:

     1.

     Mode = 1 Number = 0 def f(x): global Mode if Mode == 1: Mode = 0 return x + 5 else: Mode = 1 return x - 5 for i in range(0,5): Number += f(i)

     Versus:

     2.

     Mode = 1 Number = 0 if Mode == 1: def f(x): return x + 5 else: def f(x): return x - 5 for i in range(0,5): number += f(i)

     The first of these examples is best when you want to switch between modes while the code is running. The second one is best for if you just want one or the other. The first function will always give you the answer 15, because the mode changes while it is running. However, the second function will give you outputs of 35 or -15 depending on what you set the mode to in the first place.

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     1/5

   • Python Define IFERROR function

     Top Answer

     Answered Jul 03, 2019 · 6 votes

     The problem with iferror(1/0,0) is that function arguments are evaluated before the function is entered (this is the case in most programming languages, the one big exception being Haskell). No matter what iferror does, 1/0 runs first and throws an error.

     We must somehow delay the evaluation of 1/0 so it happens inside the function, in the context of a try block. One way is to use a string (iferror('1/0', 1)) that iferror can then eval

     . But eval should be avoided where possible, and there is a more light-weight alternative: Function bodies are not evaluated until the function is called, so we can just wrap our expression in a function and pass that:

     def iferror(success, failure, *exceptions): try: return success() except exceptions or Exception: return failuredef my_expr(): return 1/0print(iferror(my_expr, 42))

     42-

     The crucial part here is that we don't call my_expr directly. We pass it as a function into iferror, which then invokes success(), which ends up executing return 1/0.

     The only problem is that we had to pull the function argument (1/0) out of the normal flow of code and into a separate function definition, which we had to give a name (even thought it's only used once).

     These shortcomings can be avoided by using lambda, which lets us define single-expression functions inline:

     def iferror(success, failure, *exceptions): try: return success() # ^^ except exceptions or Exception: return failureprint(iferror(lambda: 1/0, 42))# ^^^^^^^

     42-

     [Live demo]

     Compared to your original attempt, only two changes were necessary: Wrap the expression in a lambda:, which delays evaluation, and use () in try: return success() to call the lambda, which triggers evaluation of the function body.

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     2/5

   • Python Pre-Define Function

     Top Answer

     Answered Nov 07, 2018 · 2 votes

     If you need a function that does not already exist, you can just define it and use its name from now on.

     For example:

     if foo: def patch_fct(tup): return 2*(np.random.random_sample(tup) - 0.5)elif bar: def patch_fct(tup): # do something elseelse: patch_fct = another_existing_function

     The chain of ifs and elses can be written a bit more smoothly with the help of a dictionary.

     For your original code, you could write

     patch_functions = {'zeros': np.zeros, 'ones': np.ones, 'rand': np.random.random_sample}

     and then use it like this:

     >>> patch_functions['zeros'](5)>>> array([0., 0., 0., 0., 0.])-

     This will automatically throw a KeyError if you are trying to access a key that does not exist in the dictionary.

     You can also put self-defined functions inside a dictionary, either by defining them prior to insertion or using anonymous lambda functions. Demo:

     >>> def fun1(tup):...: return sum(tup) + 1>>> >>> my_functions = {'my_sum': fun1, 'my_random': lambda tup: 2*(np.random.random_sample(tup) - 0.5)}>>> my_functions['my_sum']((2, 5))>>> 8>>> my_functions['my_random']((2, 5))>>> array([[-0.20203832, -0.23868021, 0.72052191, 0.72931098, -0.57160796], [-0.45117601, -0.95461634, -0.52232593, -0.24011216, -0.83875935]])

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     3/5

   • Define Python class member function with *args

     Top Answer

     Answered Apr 23, 2021 · 0 votes

     You can do just that pretty easily. Note that you can iterate through each element in args.

     class Foo: def speak(self, *args): for arg in args: print(arg, end=" ") bar = Foo()bar.speak("Hello", "I", "am", "bar")

     Output:

     Hello I am bar

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     4/5

   • Also try

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     python define function sample	python define function example

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2. learnpython.com › blog › define-function-pythonHow To Define a Function in Python | LearnPython.com

   learnpython.com › blog › define-function-python

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   Apr 15, 2021 · Defining a Function in Python: Syntax and Examples. The syntax for defining a function in Python is as follows: def function_name(arguments): block of code. And here is a description of the syntax: We start with the defkeyword to inform Python that a new function is being defined.

3. www.w3schools.com › python › python_functionsPython Functions - W3Schools

   www.w3schools.com › python › python_functions

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   Python. Functions. Previous Next . A function is a block of code which only runs when it is called. You can pass data, known as parameters, into a function. A function can return data as a result.

4. www.programiz.com › python-programming › functionPython Functions (With Examples) - Programiz

   www.programiz.com › python-programming › function

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   In Python, functions are divided into two categories: user-defined functions and standard library functions. These two differ in several ways: User-Defined Functions. These are the functions we create ourselves. They're like our custom tools, designed for specific tasks we have in mind.

5. www.geeksforgeeks.org › python-functionsPython Functions - GeeksforGeeks

   www.geeksforgeeks.org › python-functions

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   Jul 29, 2024 · A Python function is a block of reusable code that performs a specific task when called, often accepting inputs (arguments) and returning an output.

6. realpython.com › defining-your-own-python-functionDefining Your Own Python Function – Real Python

   realpython.com › defining-your-own-python-function

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   In this tutorial, you'll learn how to define and call your own Python function. You'll also learn about passing data to your function, and returning data from your function back to its calling environment.

7. note.nkmk.me › en › python-function-def-returnDefine and call functions in Python (def, return) | note.nkmk.me

   note.nkmk.me › en › python-function-def-return

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   Aug 19, 2023 · How to define and call a function in Python. In Python, functions are defined using def statements, with parameters enclosed in parentheses (), and return values are indicated by the return statement.

8. pythonbasics.org › functionsFunctions in Python (With Examples) - Python Tutorial

   pythonbasics.org › functions

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   Functions are small parts of repeatable code. Without functions we only have a long list of instructions. Functions can help you organize code. Functions can also be reused, often they are included in modules. Functions can be seen as executable code blocks. A function can be used once or more.

9. python.land › introduction-to-python › functionsPython Function: The Basics Of Code Reuse

   python.land › introduction-to-python › functions

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   Oct 31, 2023 · A Python function is a named section of a program that performs a specific task and, optionally, returns a value. Functions are the real building blocks of any programming language. We define a Python function with the def keyword.

10. pynative.com › python-functionsPython Functions [Complete Guide] – PYnative

    pynative.com › python-functions

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    Aug 2, 2022 · Python function is a block of code defined with a name. Learn to create and use the function in detail. Use function argument effectively.

11. www.freecodecamp.org › news › functions-in-python-a-beginners-guideFunctions in Python – Explained with Code Examples -...

    www.freecodecamp.org › news › functions-in-python-a-beginners-guide

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    Jul 28, 2021 · The following snippet shows the general syntax to define a function in Python: def function_name(parameters): # What the function does goes here return result. You need to use the def keyword, give your function a name, followed by a pair of parentheses, and end the line with a colon (:).