擅长:python、mysql、java
<pre><code>>>> print "%+d" % (-1)
-1
>>>
>>> print "%+d" % (1)
+1
>>> print "%+d" % (0)
+0
>>>
</code></pre>
<p>这是<a href="http://docs.python.org/library/stdtypes.html#string-formatting-operations" rel="noreferrer">the documentation</a>。</p>
<p>**更新**如果由于任何原因不能使用<code>%</code>运算符,则不需要函数:</p>
<pre><code>>>> total = -10; print "Total:" + ["", "+"][total > 0] + str(total)
Total:-10
>>> total = 0; print "Total:" + ["", "+"][total > 0] + str(total)
Total:0
>>> total = 10; print "Total:" + ["", "+"][total > 0] + str(total)
Total:+10
>>>
</code></pre>