Interpreted: platform independent, very high level, rapid development cycle
Very clear syntax: easy to learn, even just by example
Fully Object Oriented, but not mandated
No need to initialize variables
Python determines data type of variables by how they are used.
- A number expressed as and integer is an int (i = 5).
- A number with a decimal point is a float (x = 3.5).
- Character data is put in quotes and is a str (string) (st = ‘Hello, World’).
Advanced built-in data structures allows for rapid development.
Use colon and indention to identify a code block.
No need for semicolons or brackets:
n = 9 r = 1 while n > 0: r = r * n n = n – 1 print r
Initialize strings with pairs of single quotes, double quotes, or triple quotes:
a = '\t this starts with a "tab".' b = "this string has 'line feed'.\n" c = "backslash \"quotes\"." d = 'same for \'single\' quotes.' e = """The triple quote is nice for strings that take multiple lines. 'single' and "double" quotes do not need backslashes."""
Merging variables with strings:
st = "There are %d lines and %d characters in the file" % (chars, lines)
x = (1, 2, 3)
Use tuples when possible because they are more efficient than lists
Tuples are used to facilitate saving multiple values returned from a function
>>> def swap(a, b): ... return(b, a) ... >>> x = 1 >>> y = 2 >>> x, y = swap(x, y) >>> x 2 >>> y 1