## Jason M. Grant

Assistant Professor of Computer Science

## More Variables, Strings, and Arithmetic

### Variables and Types

So far, we have seen the following variable types:

1. integer (whole number, either positive or negative)
2. float(number with a decimal value)
3. string(one or more characters of text)
4. boolean (True/False)

Variables can be converted from one type to another. You should have seen this in your lab assignment:

`age = float(input("Please enter your age: "))`

In this instance, a string was converted to a floating point number. This allows the computer to treat this value as a number instead of text. Similarly, you can convert a floating point number to an integer using the `int()`function.

`age = 18.5 yearsrounded_age = int(age)`

Similarly, a string can be converted to text using the `str()`function. Python easily allows you to see the type of the variable using the `type()`function.

### String Manipulation

In this section, we explore string concatenation and indexing.

### String Methods

Python provides several built-in functions for manipulating strings. You can view all of this function in the Python documentation. Some functions include `upper()`, which converts the entire string to uppercase, `find()`, which returns the index of the first matching index, and `isalpha()`, which returns the value True if all characters are alphabetical (no numbers, spaces, etc.). A method is a special type of function and is called differently than the functions we have seen thus far. Here are a few examples: