o_18ufhmfmq19t513t3lgmn5l1qa8a.pdf

30 CHAPTER 1 ■ INSTANT HACKING: THE BASICS
Strings. Strings are really simple—they are just pieces of text. And yet there is a lot to know
about them. In this chapter, you’ve seen many ways to write them, and in Chapter 3 you
learn many ways of using them.
New Functions in This Chapter
Function
Description
abs(number)
Returns the absolute value of a number
cmath.sqrt(number)
Square root, also for negative numbers
float(object)
Converts a string or number to a floating-point number
help()
Offers interactive help
input(prompt)
Gets input from the user
int(object)
Converts a string or number to an integer
long(object)
Converts a string or number to a long integer
math.ceil(number)
Returns the ceiling of a number as a float
math.floor(number)
Returns the floor of a number as a float
math.sqrt(number)
Square root, not for negative numbers
pow(x, y[, z]) x to the power of y (modulo z)
raw_input(prompt)
Gets input from the user, as a string
repr(object)
Returns a string-representation of a value
round(number[, ndigits])
Rounds a number to a given precision
str(object)
Converts a value to a string
What Now?
Now that you know the basics of expressions, let’s move on to something a bit more advanced:
data structures. Instead of dealing with simple values (such as numbers), you’ll see how to
bunch them together in more complex structures, such as lists and dictionaries. In addition,
you’ll take another close look at strings. In Chapter 5, you learn more about statements, and
after that you’ll be ready to write some really nifty programs.