Is Python a

As you’ve seen, there are no variable type declarations in Python; this fact alonemakes for a much simpler language syntax than what you may be used to. But, formost new users, the lack of the braces and semicolons used to mark blocks and statementsin many other languages seems to be the most novel syntactic feature ofPython, so let’s explore what this means in more detail.Block DelimitersPython detects block boundaries automatically, by line indentation—that is, theempty space to the left of your code. All statements indented the same distance tothe right belong to the same block of code. In other words, the statements within ablock line up vertically, as in a column. The block ends when the end of the file or alesser-indented line is encountered, and more deeply nested blocks are simplyindented further to the right than the statements in the enclosing block.For instance, Figure 12-1 demonstrates the block structure of the following code:x = 1if x:y = 2if y:print 'block2'print 'block1'print 'block0'Block0Header-line:Block1Header-line:Block2Block0Block1Figure 12-1. Nested blocks of code: a nested block starts with a statement indented further to theright, and ends with either a statement that is indented less, or the end of the file.This code contains three blocks: the first (the top-level code of the file) is notindented at all, the second (within the outer if statement) is indented four spaces,and the third (the print statement under the nested if) is indented eight spaces.240 | Chapter 12: if Tests