REPLAndStandardPythonProgramming < IoT_Course

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<p align="center"><font face="Liberation Sans, sans-serif"><font size="6"> *Course on Internet of Things* </font></font></p>
---+ Exercises Session 1:
---++ Introductory remarks:

The scripts we are going to develop during this exercise session do not depend on any system issues: We do not use command line arguments not available in !MicroPython nor do we use any hardware specific features which are not available on a PC. The exercises can therefore be developed and run on the ESP32 but also on any standard PC with Python3 installed.
---++ Exercise 1: Use of REPL

Connect to your ESP32 with minicom or thonny. You may try the same thing running Python3 on your PC.

Using REPL:
   * <p>print “Hello World!”</p>
   * <p>read in a text using <i>input() </i>and print it</p>
   * <p>Calculate</p> <p><img align="middle" alt="calculations.png" height="52" src="%PUBURL%/UCC_Course_2021/Exercises/calculations.png" title="calculations.png" width="142" /></p>
   * <p>Calculate sin(30°) <br /> If you see errors, how do you correct them? Are the results correct?</p>
   * Finally make the "print Hello World!" command a script and execute it.
---++ Exercise 2: A simple calculator

Write a script that assigns the values 5 and 3 to the variables a and b respectively

Print the results of 4 basic arithmetic operations:
   * <p>a+b</p>
   * <p>a-b</p>
   * <p>a*b</p>
   * <p>a/b</p>
If you use integer format when printing the result, you will see the result truncated to an integer. Can you correct changing the format?

%ATTACHURL%/calculatorV1.py.txt

Improve this program asking the user to enter 2 real numbers (floats) separated by a space. This is how it should look like:

<img alt="calcOk.png" height="172" src="%ATTACHURL%/calcOk.png" title="calcOk.png" width="845" />

If this happens:

<img alt="invalidFloat.png" height="240" src="%ATTACHURL%/invalidFloat.png" title="invalidFloat.png" width="822" />

when the user mistypes and enters something that is not a real number, can you capture the error and simply ask the user to repeat his input, until you get 2 correct floating point numbers?

%ATTACHURL%/calculatorV2.py.txt

*Bonus points:* Writing a parser for user input is rather easy if the numbers and operator are separated by spaces (have a look at the split method of strings). It is quite a bit more tricky if you allow entering calculations without spaces between the operands and the operator. Can you write a parser accomplishing this?

Hint: A very elegant solution to this is the use of regular expressions and Python provides a module helping you with this:

https://docs.micropython.org/en/latest/library/ure.html

A float is defined as follows:
   * <p>zero or more spaces</p>
   * followed by one '+' or one '-'
   * followed by
      * a ‘.’ followed by at least one digit
   * or<br />
      * at least one digit followed by zero or one ‘.’ followed by zero or more digits
   * <p>followed be zero of more spaces</p>
Try your parser on this input:
| *Input* | *ok or not ok* |
| 5.3+4.7 | ok |
| 5.3++4.7 | not ok |
| 5..3 + 4.7 | not ok |
| .3+.7 | ok |
| 5.3+4b7 | not ok |
| empty string | not ok |
| 5.3+. | not ok |
| 5.3+ | not ok |
| -1--1 | ok |
| --1--1 | not ok |
Try also several spaces in between operands and operator.

%ATTACHURL%/calculatorV3.py.txt
---++ Exercise 3: Conditions

Like in exercise2, start with 2 numbers a,b with values 5 and 7. In your program check which of the 2 numbers is bigger and print the result.

Then improve the program asking the user for 2 integer numbers. Make sure he enters 2 correct numbers and capture possible errors. This is a typical output:

<img alt="conditions.png" height="188" src="%ATTACHURL%/conditions.png" title="conditions.png" width="649" />
---++ Exercise 4: The Fibonacci series

The Fibonacci number series is defined as:

F(0) = 0; F(1) = 1

F(n) = F(n-1) + F(n-2)<br /><br />
   * Calculate and print out the Fibonacci numbers up to F(n). Get n from the user where n &gt;= 0
Try your program for n=0, n=1, n=2, n=3, n=20<br /><br />
   * Ask the user up to which is the maximum number up to which you should calculate.
---++ Exercise 5: A bit of Mathematics: Calculate the sine function

Write a script that asks the user for an angle in degrees. Calculate the sine of this angle.
---++ Exercise 6: Classes

Write a Python class with methods calculating mathematical number series. These series should be calculated:
   * The Fibonacci numbers up to F(n). n is passed as parameter to the method
   * The Fibonacci numbers smaller than max. max is passed as parameter to the method
   * The prime numbers up to max
   * Factorial:<br /><img alt="factorial.png" height="41" src="%ATTACHURL%/factorial.png" title="factorial.png" width="308" />
   * The geometric number series:<br /><img alt="geometric.png" height="72" src="%ATTACHURL%/geometric.png" title="geometric.png" width="335" />
   * The harmonic number series:<br /><img alt="harmonic.png" height="72" src="%ATTACHURL%/harmonic.png" title="harmonic.png" width="76" />
 <br />Can you tell what the following series calculate?
<img alt="mathSeries.png" height="124" src="%ATTACHURL%/mathSeries.png" title="mathSeries.png" width="611" />

Add these series to your class and try. Write a test script exercising the different methods.

Please also have a look at the Wikipedia page on number series: [[https://en.wikipedia.org/wiki/Series_(mathematics)%20][https://en.wikipedia.org/wiki/Series_(mathematics)]]

In order to make this exercise run on the ESP32 you must first upload your mathSeries.py module implementing the !MathSeries class into the file system of the ESP32. Create a directory called _lib_ on the ESP32 file system and put your module there:

_ampy mkdir /lib_

_ampy put mathSeries.py /lib/mathSeries.py_

Once this is done, go to the REPL window of thonny and

_import mathSeries_

You can now create an instance of the !MathSeries class:

_series = mathSeries.MathSeries()_

When running on a PC you may want to plot the series as well. If you don't know how to plot data in Python, you will find all the information needed here:<br /> https://matplotlib.org/3.2.1/index.html

Here is the exercise sheet in odt format:

%ATTACHURL%/exercise_1.odt

-- %USERSIG{UliRaich - 2020-05-03}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
png	calcOk.png	r1	manage	21.7 K	2020-05-03 - 19:52	UliRaich
txt	calculatorV1.py.txt	r1	manage	0.4 K	2020-05-28 - 09:34	UliRaich
txt	calculatorV2.py.txt	r1	manage	1.3 K	2020-05-28 - 09:34	UliRaich
txt	calculatorV3.py.txt	r1	manage	3.2 K	2020-05-28 - 09:34	UliRaich
png	conditions.png	r1	manage	28.8 K	2020-05-03 - 20:25	UliRaich
png	conversionError.png	r1	manage	19.3 K	2020-05-03 - 19:42	UliRaich
png	e.png	r2 r1	manage	1.5 K	2022-02-08 - 16:45	UliRaich
png	euler.png	r1	manage	1.5 K	2022-02-08 - 16:50	UliRaich
odt	exercise_1.odt	r2 r1	manage	126.6 K	2022-02-08 - 17:45	UliRaich
png	factorial.png	r1	manage	2.8 K	2020-05-04 - 12:48	UliRaich
png	geometric.png	r1	manage	3.9 K	2020-05-04 - 12:48	UliRaich
png	harmonic.png	r1	manage	1.6 K	2020-05-04 - 12:53	UliRaich
png	invalidFloat.png	r1	manage	32.0 K	2020-05-08 - 13:38	UliRaich
png	ln2.png	r1	manage	2.0 K	2020-05-04 - 12:48	UliRaich
png	mathSeries.png	r3 r2 r1	manage	9.7 K	2022-02-08 - 17:36	UliRaich
png	pi.png	r1	manage	2.7 K	2020-05-04 - 12:48	UliRaich
png	wallis.png	r1	manage	6.1 K	2020-05-05 - 14:31	UliRaich
png	wallis1.png	r1	manage	14.8 K	2020-05-05 - 14:35	UliRaich
png	wallis_prod.png	r4 r3 r2 r1	manage	4.2 K	2022-01-27 - 09:46	UliRaich

Topic revision: r17 - 2022-02-08 - UliRaich