擅长:python、mysql、java
<p>格式化打印语句时,可以指定要显示的有效数字的数目。例如,<code>'%.2f' % float_value</code>将显示两个小数位。有关更详细的讨论,请参见<a href="https://stackoverflow.com/questions/455612/python-limiting-floats-to-two-decimal-points">this question</a>。在</p>
<p>你想要这样的东西:</p>
<pre><code>import math
xx = .2
userDecimals = raw_input (" Enter the number of decimal places you would lik e in the final answer: ")
userDecimals = int(userDecimals)
fmt_str = "%."+str(userDecimals)+"f"
print fmt_str % math.sqrt(1 - xx **2)
</code></pre>
<p>输出:</p>
^{pr2}$