<p>可以使用<a href="http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#boolean-indexing" rel="nofollow noreferrer">^{<cd1>}</a>和<a href="http://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.loc.html" rel="nofollow noreferrer">^{<cd2>}</a>作为按条件和列名筛选:</p>
<pre><code>s = df.loc[df['instrument_token'].eq(12295682), 'tradingsymbol']
#alternative
s = df.loc[df['instrument_token'] == 12295682, 'tradingsymbol']
</code></pre>
<p>然后得到<code>Series</code>的第一个值:</p>
<pre><code>a = s.iat[0]
a = s.iloc[0]
a = s.tolist()[0]
a = s.to_array()[0]
#general solution if not match condition and select first value failed
a = next(iter(s), 'no match')
</code></pre>
<p>另一个想法是按列<code>instrument_token</code>使用<a href="http://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.set_index.html" rel="nofollow noreferrer">^{<cd4>}</a>fo索引:</p>
<pre><code>df = df.set_index('instrument_token')
</code></pre>
<p>然后按<a href="http://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.loc.html" rel="nofollow noreferrer">^{<cd2>}</a>或
<a href="http://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.at.html" rel="nofollow noreferrer">^{<cd7>}</a>:</p>
<pre><code>a = df.loc[12295682, 'tradingsymbol']
a = df.at[12295682, 'tradingsymbol']
</code></pre>