Review 2/8

IDLE , Variables , String ←→ Integer , Storing Inputs

→ Lab Assignment: “How old will I be?” on repl.it

[[ REVIEW 0 ]]

IDLE: shell vs. editor

[[ REVIEW 1 ]]

Variables

• Variables are used to label and store data. This lets us use the same data in many places, and change the value over time.
• Variables can be named whatever you want, as long as it does NOT: have any spaces, start with a number, and/or contain any symbols except _ (underscore)
• To create a variable, we write the variable’s name followed by a single equal sign =. Everything to the right of the equal sign = is assigned to the variable and gets stored.

[[ REVIEW 2 ]]

Converting Integer → String

When we do this:

>>>  a = 124
>>>  b = 816
>>>  str(a) + str(b)

This is what Python is actually doing:

Source: Python Room

[[ REVIEW 3 ]]

Storing inputs as variables

The input() function lets you ask the user for some data. We can store a user’s input as a variable, and do stuff with it later.

Why did the last print statement fail?

Inputs are always strings!!! Therefore, age is a string.

Since age is a string, it can’t be added to 10 (an integer).

We must convert it to an integer. And there are actually two places this could happen:

You could convert it at…

• the final print statement (Line 7), or
• the actual variable assignment (Line 1)

What!!!!!