擅长:python、mysql、java
<p>您可以尝试<a href="http://pandas.pydata.org/pandas-docs/stable/generated/pandas.DataFrame.replace.html" rel="nofollow">^{<cd1>}</a>和{a2}:</p>
<pre><code>import pandas as pd
import numpy as np
my_data = np.array([[0.5, 0.2, 0.1], ["NA", 0.45, 0.2], [0.9, 0.02, "N/A"]])
df = pd.DataFrame(my_data, dtype=str)
print df.replace({r'N': np.nan}, regex=True).astype(float)
0 1 2
0 0.5 0.20 0.1
1 NaN 0.45 0.2
2 0.9 0.02 NaN
</code></pre>