computer (lesson 1-4)

• sequence - the following of one thing after another; or the order of succession
• sequence control structure - the program lines executed in the same manner as they were placed in the program
• flowchart - a visual representation of the sequence of steps needed to perform a process
• flowchart symbols:

  1. terminal interrupt
  2. input/output box
  3. process box
  4. off-page connector and on-page connector
  5. arrows
• terminal interrupt - a capsule. it starts and ends a flowchart
• input/output box - a parallelogram. it shows that an input was received by the flowchart or an output is displayed by the flowchart
• process box - a rectangle. the processes done in the code are found here
• connectors - connect the parts of the program
• off-page connector - a pentagon
• on-page connector - a circle
• arrows - show the flow of the process
• body mass index - the measurement of weight in relation to height
• 18.5 and 25 - a healthy adult bmi
• python - an interpreted, object-oriented, high-level programming language
• guido van rossum - he conceptualized python in the late 1980s. he worked as an implementer on a computer language called abc
• february 1991 - when the first version of python code (0.9.0) was published
• january 1994 - when python version 1.0 was released
• october 2000 - when python 2.0 was introduced
• versions of python:

  1. python 0.9.0
  2. python 1.0
  3. python 2.0
  4. python 3.0
• features of python:

  1. a simple and minimalistic language
  2. a high-level language
  3. an interpreted language
  4. portable
  5. extensible
• applications of python:

  1. gui-based desktop applications
  2. web frameworks and web applications
  3. enterprise and business applications
  4. language development
  5. prototyping
• www.python.org - official site of python
• when python is installed, a program called idle is also installed along with it
• hello, world - a simple program that, when run, displays the message "hello, world!"
• keywords - the reserved words in python. they cannot be used as a variable, name, function name, or any other identifier
• 33 - number of keywords in python
• identifiers - the names given to entities like classes, functions, variables, etc. they can help differentiate one entity from another
• do's in python:

  1. python is a case-sensitive language
  2. multiple words can be separated using an underscore or camel case style of writing
  3. variables should have names that are close or related to the value they hold or represent
• statements - the commands that python can execute
• newline character - the end of a statement is marked by a _
• backlash - we can extend statements over multiple lines with the line continuation character or using _
• line continuation - implied inside parentheses, brackets, and braces
• indentation - used in python to define a block of code. it makes the code look neat and clean
• syntaxerror - a message that results from incorrect indentation
• 4 - number of spaces used for indentation
• comments - make a program easier to understand. they describe that is going on inside a program
• hash symbol - used to write a comment
• another way of putting comments:

  1. three single quotes
  2. three double quotes