Demo learn python
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This document provides an overview of Python programming, including its history, installation, key features, and basic syntax. It highlights Python's versatility in applications such as web development, machine learning, and data science, while explaining fundamental concepts like variable assignment, data types, and operators. The importance of indentation and whitespace in Python coding is also emphasized.
![The + operator
The + operator produces a new tuple, list, or string whose value is the
concatenation of its arguments.
>>> (1, 2, 3) + (4, 5, 6)
(1, 2, 3, 4, 5, 6)
>>> [1, 2, 3] + [4, 5, 6]
[1, 2, 3, 4, 5, 6]
>>> “Hello” + “ ” + “World”
‘Hello World’](https://image.slidesharecdn.com/demo-learnpython-210706172149/85/Demo-learn-python-13-320.jpg)
![The * Operator
The * operator produces a new tuple, list, or string that “repeats” the
original content.
>>> (1, 2, 3) * 3
(1, 2, 3, 1, 2, 3, 1, 2, 3)
>>> [1, 2, 3] * 3
[1, 2, 3, 1, 2, 3, 1, 2, 3]
>>> “Hello” * 3
‘HelloHelloHello’](https://image.slidesharecdn.com/demo-learnpython-210706172149/85/Demo-learn-python-14-320.jpg)
Demo learn python
- 2. Overview • History • Installing & Running Python • Names & Assignment • Sequences types: Lists, Tuples, and Strings • Mutability
- 3. Brief History of Python • Invented in the Netherlands, early 90s by Guido van Rossum • Named after Monty Python • Open sourced from the beginning • Considered a scripting language, but is much more • Scalable, object oriented and functional from the beginning • Used by Google from the beginning • Increasingly popular
- 4. Python Creator “Python is an experiment in how much freedom program- mers need. Too much freedom and nobody can read another's code; too little and expressive-ness is endangered.” - Guido van Rossum
- 5. Applications of Python • Web Development • Game Development • Machine Learning and Artificial Intelligence • Data Science and Data Visualization • Desktop GUI • Web Scraping Applications • Business Applications • Audio and Video Applications • CAD Applications • Embedded Applications
- 6. Running Python • Visit www.python.org
- 7. Python script • When you call a python program from the command line the interpreter evaluates each expression in the file • Familiar mechanisms are used to provide command line arguments and/or redirect input and output • Python also has mechanisms to allow a python program to act both as a script and as a module to be imported and used by another python program
- 9. Python code sample x = 34 - 23 # A comment. y = “Hello” # Another one. z = 3.45 if z == 3.45 or y == “Hello”: x = x + 1 y = y + “ World” # String concat. print x print y
- 10. Understanding the code Indentation matters to code meaning • Block structure indicated by indentation First assignment to a variable creates it • Variable types don’t need to be declared. • Python figures out the variable types on its own. Assignment is = and comparison is == For numbers + - * / % are as expected • Special use of + for string concatenation and % for string formatting (as in C’s printf) Logical operators are words (and, or, not) not symbols The basic printing command is print
- 11. Basic Datatypes Integers (default for numbers) z = 5 / 2 # Answer 2, integer division Floats x = 3.456 Strings • Can use “” or ‘’ to specify with “abc” == ‘abc’ • Unmatched can occur within the string: “matt’s” • Use triple double-quotes for multi-line strings or strings than contain both ‘ and “ inside of them: “““a‘b“c”””
- 12. Whitespaces Whitespace is meaningful in Python: especially indentation and placement of newlines •Use a newline to end a line of code Use when must go to next line prematurely •No braces {} to mark blocks of code, use consistent indentation instead • First line with less indentation is outside of the block • First line with more indentation starts a nested block •Colons start of a new block in many constructs, e.g. function definitions, then clauses
- 13. The + operator The + operator produces a new tuple, list, or string whose value is the concatenation of its arguments. >>> (1, 2, 3) + (4, 5, 6) (1, 2, 3, 4, 5, 6) >>> [1, 2, 3] + [4, 5, 6] [1, 2, 3, 4, 5, 6] >>> “Hello” + “ ” + “World” ‘Hello World’
- 14. The * Operator The * operator produces a new tuple, list, or string that “repeats” the original content. >>> (1, 2, 3) * 3 (1, 2, 3, 1, 2, 3, 1, 2, 3) >>> [1, 2, 3] * 3 [1, 2, 3, 1, 2, 3, 1, 2, 3] >>> “Hello” * 3 ‘HelloHelloHello’