Variables, expressions, and statements. [June 28, 2011, 3:55 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:
a_name = 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.
Expressions are a subset of statements and typically return some result. Basic examples of expressions include arithmetic operations:
2 + 3
3 - 2
5 * 5
10 / 5
Operators are included in expressions and consist of symbols such as +, -, /, *, **, etc.
Learning Resources
- Python for Informatics -- Chapter 2 (Slides, Printable Slides, Streaming Video, Download Video, Lecture Audio)
Assignment
Please review the documents in the learning resources section. Be sure to complete the excercises as we are here to practice. 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 :-)