Boston Python Workshop 4/ColorWall handout

Indentation reminder
In Python, indentation matters. Everything is indented by a multiple of some number of spaces, often 4.

In  statements, you indent everything you want to be run if the if conditional is. For example:

>>> James = 35 >>> Alice = 30 >>> if James > Alice: ...    print "James is older than Alice." ... James is older than Alice. >>>

Because James really is older than Alice, the  conditional is  , so Python does execute the code indented under the if line. In this case we print "James is older than Alice."

>>> James = 35 >>> Alice = 30 >>> if James < Alice: ...    print "James is younger than Alice." ... >>>

Because James is not older than Alice, the  conditional is , so Python does not execute the code indented under the if line.

In for loops, you indent everything you want to be run each loop For example:

>>> names = ["Jessica", "Adam", "Liz"] >>> for name in names: ...    print "Hello", name ... Hello Jessica Hello Adam Hello Liz

The  line is indented 4 spaces under the. That's how Python knows to execute the print line for every name in names.