RepoLearner/Notes_PythonBasics.txt at main · DataAlchemyScribe/RepoLearner · GitHub

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Order of Operation --
=> PEMDAS - Parentheses, Exponents, Multiplication/Division, Addition/Substraction

Basic Arithmetic operators --
=> + , - , * , / , //, % , **

help() -- brief about built-in functions
=> e.g. help(round), help(print),...

Note: (Docstring) you can also use help() for user-defined functions brief by providing a """ brief """ inside the user-defined function.

e.g.
#Code
def least_difference(a, b, c):
    """Return the smallest difference between any two numbers
    among a, b and c.

    >>> least_difference(1, 5, -5)
    4
    """
    diff1 = abs(a - b)
    diff2 = abs(b - c)
    diff3 = abs(a - c)
    return min(diff1, diff2, diff3)

#Input
help(least_difference)

#Output
Help on function least_difference in module __main__:

least_difference(a, b, c)
    Return the smallest difference between any two numbers
    among a, b and c.

    >>> least_difference(1, 5, -5)
    4

Higher-Order Functions --
=> Functions that operate on onther functions
*************************************************************************

Order of Precedence for Boolean Operators --
=> not >> and >> or

List -- []
=> ordered sequences of values.
=> able to contain different types of variables.
=> Indexing is useful to access individual list elements. (starts from 0)
    Note: negative values refers from end of list
=> Slicing - list_name['start point':'end point']
    Note: this will return all list elements from start point and continuing to but not end point.
=> lists are mutable (can be modified)
=> List Functions:-
    len() , sorted() , sum() , max() , min()
=> List Methods:-
    append() , pop() , index()

Tuples -- ()
=> almost similar to list.
=> Tuples are immutable (cannot be modified).
*************************************************************************

Loops --
=> for (variable) in (object that supports iteration):
    ...

=> range() -- for (variable) in range():
                ...

=> while (conditio):
    ...

List comprehensions --
=> sqr = [n**2 for n in range(10)]
   [0,1,4,9,16,25,36,49,64,81]

--Monte Carlo Method
*************************************************************************

Strings --
=> remember ' ' can have " " and vice-versa " " can have ' '.
Note:- \ allows to have single quote (') inside the  single quoted string ' '.

=> Single quote (' '), Double quote (" "), Triple quote (""" """)

=> Strings -- sequence of characters.
=> Strings are immutable (cannot be modified).

String Methods --
=> upper() , lower() , index() , startswith() , endswith() , split() , join() , format()
*************************************************************************

Dictionaries {} --
=> built-in Python Data Structure - map keys to values
=> access keys using []
=> keys() , values() , items() -- Methods
*************************************************************************

These 3 tools will guide one to understand strange objects --
=> type() - what is this thing?
=> dir() - what can I do with it?
=> help() - tell me more!
*************************************************************************