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(= Importing math)
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=== Importing math ==
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=== Importing math ===
  
 
There's much more you can do, of course, but you need to import the math functions first.  Here's one way to do that.
 
There's much more you can do, of course, but you need to import the math functions first.  Here's one way to do that.

Revision as of 07:00, 7 February 2013

This page contains examples and links to programs used for our Research Methods - Programming with Python short course.

Very simple Python

Start a Python interactive session using the "python" command to get a >>> prompt.

Command line math

Type

>>>x=1

and then simply

>>>x

and you'll see

1


Type

>>>x=1.01

and then after you type "x" you'll see

>>>x
1.01


Clearly you have a real-time calculator in hand, so try something more exciting.

>>>x=1.01
>>>y=1.0001
x/y

and you'll see something like this

1.0098990100989902

Modify that with

>>>z=x/y
>>>z

and you'll see the same result. But now try

>>>int(z)

and you'll see

1


That is, the function int() took the integer part of z. You can put that in another variable such as

>>>a=int(z)
>>>a
1

Curiously, a seems to be an integer. It is said to be dymanically typed in this assignment. That can change. If you now add a little bit to a you'll see it turns into a floating point number

>>>a = a + 0.001
>>>a
1.001

Importing math

There's much more you can do, of course, but you need to import the math functions first. Here's one way to do that.

>>>import math

Now try

>>>math.pi

and you'll see

3.141592653589793

The functions in the math package need the "math." in front of them.

>>>math.sin(math.pi/4.)

returns

0.7071067811865475

as does

>>>math.sqrt(0.5)

Similarly

>>>4.*math.asin(math.sqrt(0.5))

returns

3.1415926535897936