Python Primer

Introduction

This is a little introduction to Python. It is not meant to teach you Python, just give you enough syntax to write scripts for Notepad++.

Basics

The key, is indentation. That separates out the blocks of code. Some people initially don’t like this approach, thinking it might be unclear or easy to get wrong - I did. Now I think it’s just great :)

There are no semi-colons (;) at the end of lines like in C or Java.

You can define a variable simply by using it.:

x = 5

To call a function, just type the name, followed by brackets, with any arguments in brackets.:

x = 5
console.write(x)

If Statements

An if statement doesn’t need brackets around the test, just a colon (:) at the end of the line. The colon signifies the start of a new block. The next line must be indented more than the if line.

The if block continues until the indentation reverts to the same indentation as the if line.:

console.write("Let's go")

if x == 3:
        console.write("So x is 3 then")
        console.write("This line is also run if x is 3")
console.write("this line is run always")

To use an else, place the else at the same level as the if, and append a colon:

if x == 3:
        console.write("So x is 3 then")
        console.write("This line is also run if x is 3")
else:
        console.write("Guess x isn't 3 this time.")
        console.write("Better luck next time")

console.write("this line is run always")

If you want an “else if”, use elif:

if x == 3:
        console.write("So x is 3 then")
        console.write("This line is also run if x is 3")
elif x == 6:
        console.write("Hey it's your lucky day, x is 6")
else:
        console.write("x is not 3 or 6 this time.")
        console.write("Better luck next time")

Functions

To define a function, just use def. Again, the indentation is important, the function definition lasts as long as the indentation stays the same:

def printNameAge(name, age):
        console.write("Hello {0}, ".format(name))
        console.write("how was your {0} birthday?".format(age))

printNameAge("Dave", 99)

Line 1 defines the function, the body of the function is lines 2 and 3. Line 5 calls the function with the arguments “Dave” and 99.

You can read about the format() function (and what the {0} in the string means) in Python‘s documentation.

To pass the function to another function (as in callbacks in Python Script), just use the name of the function without brackets:

def printNameAge(name, age):
        console.write("Hello {0}, ".format(name))
        console.write("how was your {0} birthday?".format(age))


def callFunc(func)
        console.write("Calling function...\n")
        func("Dave", 99)


callFunc(printNameAge)

Line 11 calls the callFunc function, passing the printNameAge function to it. The callFunc function then calls printNameAge on line 8.

Strings

Strings use double or single quotes. There’s no difference, but that helps if you want to include one type or other in the string.:

someString = "this is a string with a ' single quote inside"
someOther  = 'this is a string with a " double quote inside'

If you need both, just use \ to escape them:

someString = "here's a string with both types of \" in it"

If you need to use \ itself, just include two:

someString = "here's a demo of using a \\ backslash"

You can also use raw strings. These don’t need the \\ to mean \, which can make certain strings (particularly regular expressions) easier to understand. However, you also can’t escape a quote. To make a raw string, just put an r before the string

someString = r”this is also a string using a backslash”

Further Information

This guide may be extended in the future, if people request it, and either I get time, or somebody puts some time into it. There are many good sources of information on the Internet, I’ve included a couple here.

http://docs.python.org/tutorial/

http://www.tutorialspoint.com/python/python_quick_guide.htm

And all the information is available on http://www.python.org