Chapter 4 :Introducing Python Object types

Everything is an object in Python: from simple numbers to strings.

The python conceptual hierarchy

1. Programs are composed of modules
2. Modules contain statements
3. Statements contain expressions
4. Expressions create and process objects

Python’s Core Data Types

• Numbers: 124, 12.3, Decimal(), Fraction()
• Strings: 'spam’, 'a\246'
• Lists: []
• Dictionaries: {}
• Tuples: ()
• Files: open()
• Sets: {}
• Other core types: Boolean, types, None
• Program unit types: Functions, modules, classes
• Implementation related types: Compiled code, stack tracebacks

Numbers

• int
• float
• complex
• decimals
• rationals
• sets

There are two waya to print every object in Python- with full precision(as-code repr) and the second is it’s user-friendly str.

If something looks odd, try showing it with a print function

Strings

Strings are used to record both textual information as well as arbitrary collection of bytes.

Index of string starts from 0. s[0] gives the first character of the string. s[-1] gives the last item from the end in the string s