Day 4

1. Defining Functions and
using Lists in EarSketch
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1MAGIC Presenter : Fatemeh Jamshidi. June 17-22 1

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Functions
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 2
● fitMedia(), setTempo(), init(), and rang() are all
examples of functions.
● Functions allow a user to execute some
preexisting section of code without having to write it
over again.
● Functions also make code flow in a clearer way.
They reduce duplication of lines and small details
that get in the way of a clear understanding of a
script’s goals.

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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 3
Let’s take a look at how a function is defined:
Functions
● When we define a function, we use to let python know that there is a
new function being defined.
● Then we name the function, and define what kinds of parameters it expects.
● These parameters, defined through variables, allow the function to accept
arguments.
● When is called, the files are inserted into the first two
tracks to be played simultaneously, just like the original code. It also takes a
measure, meaning that you can pass it a number to make it play at particular
times.

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Assignment
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 4
How would you clean up this code?

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Data Structure
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 5
● In order to make programming easier, computer scientists have
developed data structures.
● Data structures are used to hold information of various kinds and
make manipulating that data easier. Without data structures,
storing and manipulating data can quickly become complicated
and chaotic.
For example, imagine trying to organize books without a
bookshelf.

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Lists
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 6
● One very useful data structure that we’ll frequently use is called a
list.
● Every item in the list is numbered as an index.
● A list is named just like a variable is, but needs brackets around
the items that are being placed in it. These items are separated by a
comma as follows:
beats = [HIP_HOP_GUITAR1_2M, HIP_HOP_GUITAR2_4M,
HIP_HOP_GUITAR3_4M, HIP_HOP_GUITAR4_4M]

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Lists
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 7
Once the above code is run, our bookshelf list would look
something like this:

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Lists and Randomness
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 8
Another way to use lists is with randomness. Python’s
function can be used to select from a list at a random index.
Here’s the 12 measure fill example from before with random
drums:

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Assignment
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MAGIC Presenter : Fatemeh Jamshidi. June 17-22 9
Make a list called myMusic that contains at
least 4 samples that you think will work well
together. Use for loops and functions (as
needed) use the list to create a 12 measure
composition.