Before we get too far into this chapter, we really need to cover the most obvious and special feature of Python: indentation. Python forces the user to program in a structured format. Code blocks are determined by the amount of indentation used; this is frequently referred to as "white space matters". In many other C-based languages, brackets and semicolons are used to show code grouping or end-of-line termination. Python doesn't require those; indentation is used to signify where each code block starts and ends. In this section is an example of how white space works in Python (line numbers are added for clarification). The following code shows how white space is significant:
1 x = 1
2 if x: # if x is True...
3 y = 2 # process this line
4 if y: # if y is True...
5 print("x = true, y = true") # process this...