I think the default Mac terminal colors are different from this, but you can change them in "preferences"

This is intended as a quick guide, since one of the things that got me into programming was realizing how quickly I could start on my Apple laptop without installing anything. As a practice first project, we’ll first compute the first 10 Fibonacci numbers, then write a function that will do this.

1. **Finding Python**. The easiest way to get started is to just hit “cmd+space” (this opens spotlight: my favorite Mac feature), then type “terminal”, and open the terminal. After that, it is as easy as typing `python`

, and you have either a powerful calculator, or a way to start writing scripts.

2. **Fibonacci**. As a nice first calculation, we’ll save two variables to initialize the Fibonacci sequence, then run a loop 99 times (I had to play around a bit to see how the loop count corresponded to where in the Fibonacci sequence I was). See the image for this section. Note that the spaces are very important. You need to end lines with a colon, and start lines after the colon by indenting. See below for more proper indenting.

Wikipedia claims the first Fibonacci number is 0, which I am ignoring for this post.

3. **Function**. Now to write a helper function that I can use to calculate many such numbers, I will open a text file (just in TextEdit), type in the code below, and save it as Fib.py:

` def Fib(n):`

#calculate the nth digit of the Fibonacci sequence

a,b = 1,0

for j in range(n):

a,b = a+b,a

return a

`for j in range(10):`

print Fib(j)

You can also see this post in progress behind the semi-opaque terminal!

4. **Running a script**. Now go back to the terminal window, hit “ctrl+d” to get out of Python, and navigate to the folder where you saved Fib.py. Mine was in “colcarroll/mystuff/blog”. Once there, just type “`python Fib.py`

“, and the terminal will print out anything you asked to be printed out. Above, I print out the first 10 Fibonacci numbers.

Cheers! Now go find a proper introduction. Or use Project Euler.

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