What is the Python Visual Sandbox?
The Python Visual Sandbox is a
collection of interactive online applications containing animations
which visualize the execution of Python programs. You can
experiment and practise programming "in micro-scale" in order to get a
better understanding of algorithms and Python programming technique.
The tasks differ in their level of difficulty. Note the light bulbs!
Registration
You need
a password for playing in the Python Visual
Sandbox. Please register to
obtain a password. It takes only a minute.
Points
Playing in the
Python Visual sandbox you can earn credits (points). For each Python
Visual (only first session) you get 20 points. You just
have to watch each animation from the beginning
to the end at least one time and answer the questions at the end. In Python Puzzle and Python Quiz it depends on your
performance, how many points you earn. If you want to know how many
points you have collected yet, click here.
Python Visual
Watch movies that visualize a small Python program or
some programming principle in different ways. Decide, which animation
explains best!
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regular
expressions
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Regular expressions
are patterns which match certain strings. Imagine, how they work.
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list
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Lists are
mutable objects. What does this mean?
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iteration
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Judge
different analogies for iterations.
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multilist
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Lists
are mutable objects. Discover the magic of changes in a list of lists
(multilist).
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factorial |
How
does a recursive function compute the
factorial n! ? |
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Fibonacci
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How
does a recursive function compute the n-th Fibonacci
number? |
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mirror
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A
recursive function arranges the letters of a
word in reverse order. It turns "roma" to
"amor". How does this work? |
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sort |
A
list of numbers is sorted applying the
algorithm "straight selection"
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return
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What
happens, when a function returns something?
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Python Puzzle
In a
Python Puzzle
you can manipulate fragments of program code on the screen. Build a
program using given statements and test it! If your program is a
logically correct solution of the problem, you earn points. A Python Puzzle
is somewhat like a riddle. There are animations which help you finding
the solution.
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recursion |
Define a function that counts the occurencies
of a certain letter in a string.
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straight
selection
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Define functions that sort a list of numbers.
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multilist
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We model a group of
persons using a list of lists. Define functions that access this list.
There are 3 tasks and one hint for each task which illustrates how the
function works. Maximal time
is 600 seconds. Be quick in order to get bonus points
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multilist (part 2)
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We model a group of
persons using a list of lists. Define more functions which access this
list. There
are 4 tasks and one hint for each task. Maximal time
is 800 seconds. |
The following puzzles
are about assertions. An assertion is a logical condition that must be
true while the program is running. Using assert statements you can
verify the logical correctness of your program. When an assertion
fails, the interpreter stops the execution of the program and raises an
exception (assertion error). This helps the programmer to find the
logical error in the script.
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first
steps
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Practise
the use of assert statements and make a Python script "logically safe".
The more
(correct) assertions you can pu into the script the more points you
earn.
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reverse
words
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There
are three programs which arrange the
letters of a word in reverse order. Add as many assertions as
possible!
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assertions for
quicksort
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Quicksort is a very fast sorting algorithm
invented by Hoare. Increase the "logical safety" of different Quicksort
implementations by adding assert statements. This is also a nice
exercise in logic.
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Python Quiz
How well can analogies illustrate a running program?
In a Python
Quiz you have to decide whether an analogy fits to a Python
statement or not. When you are quick, you get bonus points. But
be careful! Wrong assignments will lead
to penality points!
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assign
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You see very simple Python programs just
consisting of a few assign statements. Which visual models are
appropriate visualizations of what is going on?
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list
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A group of persons
is modeled by a list of tuples. A Python function takes such a
list as input and returns the names of all persons that are older
than age.
Which analogies fit to the statements of the program?
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objects
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In an object oriented
program objects interact by exchanging messages. What does that mean?
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Feedback
Any ideas,
comments, criticisms or questions? Write an e-mail to me!
