Python Variables & Strings

Code Example 1 – mary.py

#A simple program.
print "Mary had a little lamb,"
print "its fleece was white as snow;"
print "and everywhere that Mary went",
print "her lamb was sure to go."

Code Example 2 – mary.py output

Mary had a little lamb,
its fleece was white as snow;
and everywhere that Mary went her lamb was sure to go.

Variables
Now let's start introducing variables. Variables store a value, that can be looked at or changed at a later time. Let's make a program that uses variables. Open up IDLE and click 'File > New Window'. A new window now appears, and it is easy to type in programs.

Code Example 3 – Variables

#Variables demonstrated
print "This program is a demo of variables."
v = 1
print "The value of v is now", v
v = v + 1
print "v now equals itself plus one, making it worth", v
v = 2
print "v can store any numerical value, to be used elsewhere."
print "For example, in a sentence. v is now worth", v
print "v times 5 equals", v * 5
print "But v still only remains", v
print "To make v five times bigger, you would have to type v = v * 5"
v = v * 5
print "There you go, now v equals", v, "and not", v / 5

Note that if you just want to modify a variable's value with respect to itself, there are shortcuts. These are called augmented assignment operators:

Table 1 – Augmented operators

Standard form	Augmented
v = v + 5	v += 5
v = v - 5	v -= 5
v = v * 5	v *= 5
v = v / 5	v /= 5

Strings [edit]

As you can see, variables store values, for use at a later time. You can change them at any time. You can put in more than numbers, though. Variables can hold things like text. A variable that holds text is called a string. Try this program:

Code Example 4 – Strings

#Giving variables text, and adding text.
word1 = "Good"
word2 = "morning"
word3 = "to you too!"
print word1, word2
sentence = word1 + " " + word2 + " " + word3
print sentence

The output will be:

Code Example 5 – String output

Good morning
Good morning to you too!

As you see, the variables above were holding text. Variable names can also be longer than one letter—here, we had word1, word2, and word3. As you can also see, strings can be added together to make longer words or sentences. However, spaces aren't added in between the words—hence me putting in the " " things (there is one space between those).

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