擅长:python、mysql、java
<p>使用<a href="http://docs.python.org/library/string.html#formatstrings" rel="noreferrer">new string format</a></p>
<pre><code>>>> '{0:+} number'.format(1)
'+1 number'
>>> '{0:+} number'.format(-1)
'-1 number'
>>> '{0:+} number'.format(-37)
'-37 number'
>>> '{0:+} number'.format(37)
'+37 number'
# As the questions ask for it, little trick for not printing it on 0
>>> number = 1
>>> '{0:{1}} number'.format(number, '+' if number else '')
'+1 number'
>>> number = 0
>>> '{0:{1}} number'.format(number, '+' if number else '')
'0 number'
</code></pre>
<p>建议使用<code>%</code>运算符</p>