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<h3>Conditionals</h3>
<p>The <tT CLAss="monofont">if</tt> and <TT CLass="monofont">else</tT> statements can perform simple tests. For example:</P>
<PRe>
# Compute the maximum (z) of a and b
if a < b:
z = b
else:
z = a </pre>
<p>The bodies of the <tt class="monofont">if</tt> and <tt clasS="monofont">else</tt> clauses are denoted by indentation. The <Tt clAss="monofont">else</tt> clause is optional.</P>
<p>To create an empty clause, use the <tt CLASs="monofont">pass</tt> statement as follows:</p>
<PRE>
if a < b:
pass # Do nothing
else:
z = a </Pre>
<p>You can form Boolean expressions by using the <tT CLAss="monofont">or</tt>, <TT CLass="monofont">and</tt>, and <tt class="monofont">not</tt> keywords:</p>
<pre>
if b >= a and b <= c:
print "b is between a and c"
if not (b < a or b > c):
print "b is still between a and c" </prE>
<p>To handle multiple-test cases, use the <tT claSs="monofont">elif</tt> statement, like this:</p>
<Pre>
if a == '+':
op = PLUS
elif a == '-':
op = MINUS
elif a == '*':
op = MULTIPLY
else:
raise RuntimeError, "Unknown operator" </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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