Python IDLE

You can run commands directly into the IDLE shell.  From the command prompt type IDLE and hit enter.  This should launch the IDLE Python Interpreter.  Do this now.

A window like the one above should appear.

Now let’s explore the IDLE and Python commands at the same time.  Type the following into the IDLE then hit return.

>>>3 + 2
output: 5

>>>10-2
output: 8

>>>2*2
output: 4

>>>4/2
output: 2.0   #dividing 2 integers returns a float (float i a number with a decimal point)

>>>4 / 2 + 10
output:  12

>>>4 / (2 + 10)
output:  .3333333  #because Python performs tasks in the parenthesis first

>>>2**3  #exponents 2 x 2 x 2
output:  8

>>>2**4  # to the 4th power 2 x 2 x 2 x 2
output:  16

>>>14 // 3
output:  4  #this is the whole number from division

>>>14%3
output:  2  #this caluclates the remainder, good for finding even numbers

>>>abs(-4)
output:  4  #absolute value

>>>min(1,2,3,4,5)
output:  1  #finds the minimum value in the set

>>>max(1,2,3,4,5)
output:  5 #finds the maximum value in a set

 

Now try these boolean expressions (boolean is either True or False)

>>> 2 < 3
output: True

>>>3 < 3
output: False

>>>4 – 1 >= 2 + 1
output:  True

>>>5 != 6
output:  True  # != means not equal to

 

Let’s try some strings.  Notice how IDLE remembers what is typed on the lines above.  You can type a program line by line if you choose.

>>>print(“Hi Ho “)
output:  Hi Ho

>>>print(“Hi ho ” * 5)
output:  Hi ho Hi ho Hi ho Hi ho Hi ho

>>>myName = “Fergie”

>>>print(“myName”)
output:  myName  #just printed what was in the quotes

>>>print(myName)
output:  Fergie  #recalled the variable value

>>>place = “Cafe”

>>>print(place + myName)
output: CafeFergie

>>>print(place + ” ” + myName)
output:  Cafe Fergie

 

Notes:

Minus and division do not work with strings since there is no common sense way to apply them to strings.

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