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<h3>Functions</h3>
<p>You use the <tT CLAss="monofont">def</tt> statement to create a function, as shown in the following example:</P>
<PRE>
def remainder(a,b):
q = a/b
r = a - q*b
return r </pre>
<p>To invoke a function, simply use the name of the function followed by its arguments enclosed in parentheses, such as <TT CLass="monofont">result = remainder(37,15)</tt>. You can use a tuple to return multiple values from a function, as in the following example:</p>
<pre>
def divide(a,b):
q = a/b # If a and b are integers, q is an integer
r = a - q*b
return (q,r) </pre>
<p>When returning multiple values in a tuple, it抯 often useful to invoke the function as follows:</p>
<pre>
quotient, remainder = divide(1456,33) </pre>
<P>To assign a default value to a parameter, use assignment:</p>
<pRe>
def connect(hostname,port,timeout=300):
# Function body </prE>
<p>When default values are given in a function definition, they can be omitted from subsequent function calls. For example:</p>
<prE>
connect('www.python.org', 80) </pre>
<P>You also can invoke functions by using keyword arguments and supplying the arguments in arbitrary order. For example:</P>
<PRe>
connect(port=80,hostname="www.python.org") </pre>
<P>When variables are created or assigned inside a function, their scope is local. To modify the value of a global variable from inside a function, use the <TT Class="monofont">global</TT> statement as follows:</P>
<Pre>
a = 4.5
...
def foo():
global a
a = 8.8 # Changes the global variable a </prE>
</FONt>
<P><TABLE width="100%" border=0><TR valign="top"><TD><font size=1 color="#C0C0C0"><br></font></TD><TD align=right><font size=1 color="#C0C0C0">Last updated on 3/28/2002<br>Python Essential Reference, Second Edition, © 2002 New Riders Publishing</font></TD></TR></TABLE></P>
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