Programming Articles

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How to run Python functions from command line?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 12-Mar-2026 2K+ Views

To run Python functions from the command line, you save the function in a .py file and then invoke it using the Python interpreter. There are several approaches − using sys.argv, the -c flag, or the argparse module. Using sys.argv with __name__ Guard The most common approach is to use sys.argv to read command-line arguments and the if __name__ == "__main__" guard to call your function when the script is executed directly. The first item in sys.argv is the script name, and subsequent items are the arguments passed. Note that all command-line arguments are received as strings, so you must ...

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Are Python functions objects?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 12-Mar-2026 424 Views

Yes, Python functions are full objects. Python creates function objects when you use a def statement or a lambda expression. Like any other object, functions can be assigned to variables, passed as arguments, returned from other functions, and even have custom attributes. Functions Have a Type and Support Attributes Since functions are objects, they have a type (function) and you can assign custom attributes to them ? Example def foo(): pass foo.score = 20 print(type(foo)) print(foo.score) print(type(lambda x: x)) The output of the above code is ? 20 ...

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How can a Python function return a function?

Sarika Singh
Sarika Singh
Updated on 12-Mar-2026 19K+ Views

In Python, functions are treated as first-class objects, which means that all functions in Python are treated like any other object or variable. You can assign a function to a variable, pass it as an argument to another function, return it from a function, or even store it in data structures like lists. One very useful feature in Python is that a function can return another function. This means you can define a function inside another function and return it as a result. This is used in advanced programming concepts like closures, decorators, and higher-order functions. Returning a Simple Function ...

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How can we define a Python function at runtime?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 12-Mar-2026 106 Views

We can define a python function and execute it at runtime by importing the types module and using its function types.FunctionType() as follows This code works at the python prompt as shown. First we import the types module. Then we run the command dynf=…; then we call the function dynf() to get the output as shown import types dynf = types.FunctionType(compile('print("Really Works")', 'dyn.py', 'exec'), {}) dynf() Output Really Works Defining a Python function at runtime can be useful in a variety of situations, such as when you need to ...

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What are Python function attributes?

Tarun Chandra
Tarun Chandra
Updated on 12-Mar-2026 6 Views

Python is made up of objects but can also be used in other ways. Similarly, functions are also made up of objects, since they are objects they have attributes like identifier, title, inputs, outputs, etc. The value of an attribute cannot be changed once it has been set. To set the value of an attribute we use a function setattr and to know what value has been set as the attribute we use a function getattr. To access the attributes of a function we use the ‘.’ Operator. Some of the attributes have a special functionality such that they can ...

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How can we create recursive functions in Python?

Sarika Singh
Sarika Singh
Updated on 12-Mar-2026 4K+ Views

Recursion is a process where a function calls itself repeatedly with new input values, slowly moving toward a condition where it stops. This stopping condition is called the base case. It prevents the function from running endlessly and allows it to return a final result. In Python, we can create recursive functions by simply defining a function that calls itself. Every recursive function has two main components − Recursive Case: This is when the function calls itself to solve a smaller part of the problem. It keeps the process going. Base Case: This is the stopping point. It tells ...

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How to get a list of parameter names inside Python function?

Rajendra Dharmkar
Rajendra Dharmkar
Updated on 12-Mar-2026 3K+ Views

To get a list of parameter names inside a Python function, you can use the inspect module. This module provides several functions that let you examine the properties of Python objects, including function signatures, parameter names, and default values. Using inspect.getfullargspec() The inspect.getfullargspec() function returns a named tuple containing information about a function's parameters, including argument names, variable args, keyword args, and default values ? Example import inspect def aMethod(arg1, arg2): pass print(inspect.getfullargspec(aMethod)) def foo(a, b, c=4, *arglist, **keywords): pass print(inspect.getfullargspec(foo)) The output of the above ...

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How to wrap python object in C/C++?

Gireesha Devara
Gireesha Devara
Updated on 12-Mar-2026 648 Views

To wrap existing C or C++ functionality in Python, there are number of options available, which are: Manual wrapping using PyMethodDef and Py_InitModule, SWIG, Pyrex, ctypes, SIP, Boost.Python, and pybind1. Using the SWIG Module Let’s take a C function and then tune it to python using SWIG. The SWIG stands for “Simple Wrapper Interface Generator”, and it is capable of wrapping C in a large variety of languages like python, PHP, TCL etc. Example Consider simple factorial function fact() in example.c file. /* File : example.c */ #include // calculate factorial int fact(int n) { ...

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How to check if a matrix is invertible or not in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 11-Mar-2026 1K+ Views

If the matrix is singular then it is not invertible and if it is non−singular then it is invertible. Therefore, we can check if a matrix is singular or not. We can use is.singular.matrix function of matrixcalc for this purpose. For example, if we have a matrix called M then to check whether it is invertible or not, we can use is.singular.matrix(M).Example1Loading matrixcalc package and creating a matrix −library(matrixcalc) M1

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How to create a vector with all dates in a particular year in R?

Nizamuddin Siddiqui
Nizamuddin Siddiqui
Updated on 11-Mar-2026 1K+ Views

We know that some years are leap years and some are normal years. The leap years have 366 days and the normal years have 365 days. To create a vector with all dates in a particular year we can use first date and the last date of the year by reading them with as.Date and creating a sequence with seq function. Check out the below examples to understand how it is done.Example1Creating a vector with dates in year 2020 −seq(as.Date("2020-01-01"), as.Date("2020-12-31"), by="1 day")Output[1] "2020−01−01" "2020−01−02" "2020−01−03" "2020−01−04" "2020−01−05" [6] "2020−01−06" "2020−01−07" "2020−01−08" "2020−01−09" "2020−01−10" [11] "2020−01−11" "2020−01−12" "2020−01−13" "2020−01−14" "2020−01−15" ...

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