<p>您将所有变量括在单引号中,因此比较字符串<code>"a"</code>与字符串<code>"b"</code>,而不是将变量<code>a</code>中包含的浮点数与变量{<cd4>}中的相同</p>
<p>同样值得指出的是:</p>
<p><strong>这是您的原始代码,用于向用户请求两个浮点数</strong></p>
<pre><code>a = raw_input('podaj liczbę A : ')
b = raw_input('podaj liczbę B : ')
a = float(a)
b = float(b)
</code></pre>
<p><strong>如果您使用的是Python 2.x,则可以使用</strong></p>
<p>我在下面的评论中被<a href="https://stackoverflow.com/users/908494/abarnert">abarnert</a>更正了。只是为了教化:</p>
<blockquote>
<p>I wouldn't suggest using input instead of raw_input and float. The latter guarantees that you get floats; the former could get, say, the result of calling <code>__import__('os').system('rm -rf /')</code>, which is probably something you don't want</p>
</blockquote>
^{pr2}$
<p><strong>如果不是,则可能需要包含try/catch块,该块将强制变量为您需要的类型</strong></p>
<pre><code>a_verifying = True
while a_verifying:
a = input('podaj liczbę A : ')
try:
a = float(a)
a_verifying = False
except ValueError as e:
a = input('podaj liczbę A : ')
b_verifying = True
while b_verifying:
b = input('podaj liczbę B : ')
try:
b = float(b)
b_verifying = False
except ValueError as e:
b = input('podaj liczbę B : ')
</code></pre>