擅长:python、mysql、java
<p>只需使它成为一个函数,它可以返回某个值,而不是操纵全局,更易于维护!在</p>
<pre><code>def get_num(msg):
while True:
try:
return int(raw_input(msg)) # number of rows should be int
except ValueError:
print "The value you entered isn't a valid number, please try again."
num_rows = get_num("Enter number of rows: ")
print num_rows
</code></pre>
<p>而不是你提到的<code>numTest(cellSize, "Enter cell size: ")</code>,
你应该做<code>cellSize = get_num("Enter cell size: ")</code>。最好是返回值。在</p>
<p>对于<code>int</code>和<code>float</code>,可以将此函数设为更通用的函数,如下所示:</p>
^{pr2}$
<p>现在您还可以:</p>
<pre><code>x = get_num("test") # normal int
x = get_num("foo", float)
</code></pre>