Parameters (Formal parameter) and Arguments (Actual parameter)

Some functions require arguments.

For example, when you call math.sqrt you pass a number as an argument. Some functions take more than one argument: math.pow takes two, the base and the exponent.

Inside the function, the arguments are assigned to variables called parameters. Here is a definition for a function that takes an argument

def print_twice(bruce):
print(bruce)
print(bruce)

This function assigns the argument to a parameter named bruce. When the function is called, it prints the value of the parameter (whatever it is) twice. This function works with any value that can be printed.

>>> print_twice('Spam') # Spam is an argument
Spam
Spam
>>> print_twice(42) # 42 is an argument
42
42
>>> print_twice(math.pi) # math.pi is evaluated and the value is an arguement
3.14159265359
3.14159265359

You can also use a variable as an argument

>>> michael = 'Karpagam Institute of Technology.'
>>> print_twice(michael)
Karpagam Institute of Technology.
Karpagam Institute of Technology.

References

  • Allen B. Downey, “Think Python: How to Think Like a Computer Scientist‘‘, 2nd edition, Updated for Python 3, Shroff/O‘Reilly Publishers, 2016 (http://greenteapress.com/wp/thinkpython/)
  • Guido van Rossum and Fred L. Drake Jr, ―An Introduction to Python – Revised and updated for Python 3.2, Network Theory Ltd., 2011.
  • John V Guttag, ―Introduction to Computation and Programming Using Python‘‘, Revised and expanded Edition, MIT Press , 2013
  • Robert Sedgewick, Kevin Wayne, Robert Dondero, ―Introduction to Programming in Python: An Inter-disciplinary Approach, Pearson India Education Services Pvt. Ltd., 2016.
  • Timothy A. Budd, ―Exploring Python‖, Mc-Graw Hill Education (India) Private Ltd.,, 2015. 4. Kenneth A. Lambert, ―Fundamentals of Python: First Programs‖, CENGAGE Learning, 2012.
  • Charles Dierbach, ―Introduction to Computer Science using Python: A Computational Problem-Solving Focus, Wiley India Edition, 2013.
  • Paul Gries, Jennifer Campbell and Jason Montojo, ―Practical Programming: An Introduction to Computer Science using Python 3‖, Second edition, Pragmatic Programmers, LLC, 2013.