Changes

:In advance of this lab, you will install a current distribution of Linux to be used as in a host machineVirtual Machine on your external SSD. You will NOT be required to setup Virtual Machines for do all of your future work within this lab VM (that will be covered in a future labincluding quizzes!). You will then setup your Python scripting environment on your host machine, including the setup the of '''python''' libraries and also the setup of a user-friendly interactive Python environment called '''ipython'''. You will also install additional framework tools (such as '''git''', '''vim''', and '''tmux''') to be used in later labs.

:After selecting an appropriate text editor to use, then you will start to create '''Python''' scripts to learn basic operations such as: '''printing text''', '''using variablesobjects''', and performing '''math operations'''.

:Centos 7 - release 1161 1810 will be used for this course. The purpose for this is to allow you to use a consistent and stable '''RedHat''' based OS, and to lower the amount of new linux distros that you need to learn.

:::*Download at Seneca College: CentOS 7 Full Install DVD (image file): http://belmont.senecacollege.ca/pub/centos/7/isos/x86_64/CentOS-7-x86_64-DVD-16111810.iso:::*Download outside Seneca College: http://mirror.csclub.uwaterloo.ca/centos/7/isos/x86_64/CentOS-7-x86_64-EverythingDVD-17081810.iso

::*'''CPUs:''' 4(Number of processors: 1, Number of cores per processor: 4)

:#Regardless of the Linux distribution that is used for this course, these lab will be using and referring to the current version of '''Centos7CentOS 7''' (Graphical Desktop) for our main Linux machine. When creating your VM, refer to the '''Details / Minimum Requirements''' section above for assistance. :#Install Centos7 CentOS 7 VM selecting the default partitions. When you have finished the installation of Centos7CentOS 7, you may proceed to the next step.<blockquote style="margin-left:35px;">{{Admon/important|style="padding-left:25px"|Unit Evaluation Feedback Scripts|Each '''Part''' (within an 'Investigation) is referred to as a '''Unit'''. Each Unit will require that the student download and run a '''Unit Evaluation Feedback Script''', which provides the OPS435 student "real-time feedback" of their completed work.<br>This feedback is not considered to be perfect or fool-proof; however, it may provide feedback (hints) in case a student gets stuck or experiences an error when performing administration tasks or when creating their Python scripts. These unit evaluation feedback scripts can also be used to confirm that the student's Python script is on the right track, and provide a consistent record of their Python scripting progress throughout their labs.}}</blockquote>

<!--<ol><li value="3" style="margin-left:25px;">Issue the following commands (as a regular user) in order to setup, download and run the first unit evaluation feedback script:<br><source lang="bash">

In order to learn how to use python on your Linux machine, it is important to setup your Linux environment and learn how to interact with a Python shell. The following should be done on a terminal as the superuser (i.e. root).

<li style="margin-left:25px;">Issue Exit from the superuser shell to your regular user shell and issue the following commands in your shell to check your work for this section:<source lang="bash">mkdir -p ~/ops435/lab1/

:#Make sure you're using your regular user login and not using the root user for the following section.

:In this investigation we will start writing our very first python scripts. These will be very basic and help us practice syntax and foundation skills, such as: outputting text to the screen, storing data inside variablesobjects, and using math operators. <blockquote style="margin-left:35px;">{{Admon/important|style="padding-left:25px"|Object and Variable|The terms '''object''' and '''variable''' are used to refer to a data item in computer programming. The term '''variable''' are mostly used in 3rd generation programming/scripting languages (e.g. bash) while the term '''object''' is preferred in object oriented programming/scripting languages like Python. In the context of Python programming/scripting, When you see the term '''variable''' in the lab instructions, it can be replaced by the term '''object'''.}}</blockquote> 

You will learn to create a simple python script in this section. This python script will just print the text "hello world". The "hello world" an old traditional first program students usually are taught to create, which is based on the first programming example from the first C programming text co-written by Dennis Ritchie, the creator of the C programming language and Brian Kernighan. You will learn how to run the python script in the ipython3 python3 shell as well as learn how to run the python script from the bash shell.

</source>And run it from the command-line: <source>python3 ./testlab1a.py</source>You will notice that nothing is printed even though we called the "print()" function. This is because we didn't pass any arguments to it, lets try again.<br><br>

=== PART 2 - Working with Variables Python Objects ===

:A variable In Python, an object is used to store data for use later in the program. This data can be a string, integer, decimal number, characters, etc. We will only be covering '''string''' and '''integer''' variables in this lab. You will learn and use other variable python object types in future labs.

==== String Variables Objects ====

:String variables objects contain text to be used in your program. Examples of strings could be user-names, full-names, item descriptions, etc. We will now demonstrate to assign a string to a variable an object and how to display contents stored in a string variablesobject.

:#Let's make a new variable object containing a value:<source lang="python">

:#Now lets try something new, we are going to print out the string and concatenate/combine it with another string. The plus sign can be used to join 2 strings together. However, make sure that your variable object is always outside the quotes, or it will not resolve to a value.<source lang="python">

::::* The script should use a single variable object called "name"::::* The value of the "name" variable object should be "Isaac"

<li style="margin-left:25px;"> Before proceeding, make certain that you identify any and all errors in "lab1b.py". When the check script tells you everything is "ok", you may procede proceed to the next step.</li></ol>

==== Integer VariablesObjects====

:Integer variables In Python, integer objects are used to store a an integer numbers that can be used for mathematical operations (discussed in the next section). Integers do NOT contain decimals, and they can be signed (+ or -) or unsigned. Here we will store integers in a variableobject, perform math operations, and display the results.

:#Lets create some new variables objects to play with.<source lang="python">

:#You can print the values in those variablesinteger objects:<source lang="python">

:#Now we will make a new variable integer object and try some math:<source lang="python">

</source>This will add the values contained in the variables integer objects together, providing a sum. However you will note that there is no output. Let's inspect the new value:<source lang="python">

</source>What happened? Did you receive an error? This will may have been the first time you've seen this error, but it won't be the last. What we tried to do is combine a string with a number, and this won't work.<br><br>In order to use display this number as a string we will use the "str()" function on it. The "str()" function will return a string of your number and provide it as a argument to "print()". This function will not change the value of your variableobject, your variable object is still a an intergerobject.<br><br>

:::* The script should have a variable an object called '''name''':::* The script should have a variable an object called '''age''':::* The value of the '''name''' variable object should be '''Isaac''':::* The variable object '''age''' should contain a integer:::* The value of the '''age''' variable object should be '''72'''

<li style="margin-left:25px;">Before moving on to the next step make sure you identify any and all errors in "lab1c.py". When the check script tells you everything is "ok", you may procede proceed to the next step.</li>

::* The variable object '''x''' should contain a integer with the value '''10'''::* The variable object '''y''' should contain a integer with the value '''2'''::* The variable object '''z''' should contain a integer with the value '''5'''::* The script, when executed, should print out "10 + 2 * 5 = 20" (the printout should change if the values in the variables objects change)

<br>:'''For sections A & B:''' ::<brspan style=color:green;font-size:1.5em;">&#x2713;</span> Submit your output and Python scrips via Blackboard instead.