Variables, expressions, and statements. [Oct. 5, 2011, 8:03 p.m.]
Lets look at three components of many programming languages.
Three primary tools we will be working with are:
- Statements - small parts of a program that do not necessarily return a result. A program is formed by a sequence of one or more statements.
- Names (a.k.a. variables) - pointers to data stored in memory.
- Expressions - combination of names, symbols, functions, and/or operators that return another value.
These three aspects are fundamental to programming in general and will be explored throughout this course.
Examples:
In Python, statements can take many forms and work with many programming elements. For example, assigning a name to a value:
Names are labels that point to a specific item in the computer's memory. With the above example, a_name points to the memory location of value.
a_name = value
Expressions are a subset of statements and typically return some result. Basic examples of expressions include arithmetic operations:
Operators are included in expressions and consist of symbols such as +, -, /, *, **, etc.
2 + 3 3 - 2 5 * 5 10 / 5
Learning Resources
- Python for Informatics -- Chapter 2 (Slides, Printable Slides, Streaming Video, Download Video, Lecture Audio)
Assignment
- Review the documents in the learning resources section.
- Be sure to complete the excercises as we are here to practice.
- Copy your completed excercises and share them via a pastebin service such as dPaste.
If you have any questions or difficulties post them here and we will work together to make sure that everyone has a positive learning experience. Please also post ideas and insights into these concepts. We can learn a lot from each others' perspectives and experience :-)