Fundamentals of Python programming:
Following
below are the fundamental constructs of Python programming:
- Python Data types
- Python Operators
- Conditional Statements
- Looping Constructs
- Python functions
i) Python Data types:
Python programming
language is the dynamically typed. Hence explicit type define not required for
the variables, methods etc.,
List of data types:
- Numerical data types – int, float, complex
- String data type - str
- Data structure data types – list, set, dict and tuple
Numerical data types:
String data type:
Strings are identified as a set of characters represented in
the quotations either in (‘ ‘ , “ “, “”” “””, ‘’’ ‘’’).
Data structure data
types:
Following are the data structure data types:
- list,
- set,
- dict and
- tuple
List:
List is an ordered sequence of items.
Note:
All the items in a list do not
need to be of the same type.
Declaration:
Separated by commas are enclosed
within brackets [ ].
Slicing operator [ ]:
To extract an item or a range of
items from a list. Index starts form 0 in Python.
Example:
Python Set:
Set is an unordered
collection of unique items.
Declaration:
Set is defined by values
separated by comma inside curly braces { }.
Note:
- Items in a set are not ordered and not indexed so slicing operator won’t work with sets
- We can perform set operations like union, intersection on two sets.
- Set have unique values which in turn eliminate duplicates.
Example:
Python Dictionary:
Dictionary is an un-ordered collection of key-value pairs.
Declaration:
In Python, dictionaries are
defined within braces {} with each item being a pair in the form
key:value. Key and value can be of any type.
Note:
To retrieve value of dictionary can be done through only the key.
Example:
Python Tuple:
Tuple is an ordered sequence
of items same like list.
Note:
The only difference is that
tuples are immutable. Tuples once created cannot be modified, it returns an
exception,
Tuples are used to write and protect
data, are usually faster than list as it cannot change dynamically.
Declaration:
Separated by commas within
parenthesis or braces,
Slicing operator [ ]:
For tuples, using slicing
operator, only retrieving the values can be allowed, but not allow
the value change.
Example:
ii) Python operators:
Please follow the blog post for Python operators
iii) Python conditional statements:
Please follow the blog post for Python conditional statements
iv) Looping constructs:
Example:
v) Python functions: source
A function is a block of code which only runs when it is called. We can pass data known as parameters into a function. functions can return data as a result and provides a re usability of code.
There are three types of functions:
- User defined functions
- Pre-defined functions
- Lambda functions
User-defined functions:
Let's explore about user defined functions:
In Python, user defined function are created using the def keyword and called by using function name followed by parenthesis.
Syntax and Example:
Function parameters/arguments:
There are various ways using function arguments based on the use cases:
- Default function arguments
- Variable length arguments
- Keyword arguments
Default function arguments:
Default function argument values indicates, the function will take that value if no argument value is passed during function call and overrides the value if any explicit values for the argument. The default value is assigned by using assignment(=) operator.
Syntax and Example:
Variable length arguments:
Variable length arguments is used to pass a variable number of arguments to a function. It is used to pass a non-keyworded, variable-length argument list with help of special syntax *args.
Syntax and Example:
Keyword arguments:
Keyword arguments in python is used to pass a keyworded, variable-length argument list. We use the name kwargs with the special syntax **kwargs.
Syntax and Example:
Lambda(Anonymous functions):
Lambda function can have any number of arguments but only one expression as a return statement and these functions are mostly used on map, filter, reduce functions etc.,
Note:
Lambda functions are syntactically restricted to a single expression.
Syntax:
#Python lambda functions - Syntax
'''
lambda args: return statement
'''
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