How to concatenate multiple column values into a single column in Panda dataframe
<p>This question is same to <a href="http://stackoverflow.com/questions/11858472/pandas-combine-string-and-int-columns">this posted</a> earlier. I want to concatenate three columns instead of concatenating two columns:</p>

<p>Here is the combining two columns:</p>

<pre><code>df = DataFrame({'foo':['a','b','c'], 'bar':[1, 2, 3], 'new':['apple', 'banana', 'pear']})

df['combined']=df.apply(lambda x:'%s_%s' % (x['foo'],x['bar']),axis=1)

df
    bar foo new combined
0   1   a   apple   a_1
1   2   b   banana  b_2
2   3   c   pear    c_3
</code></pre>

<p>I want to combine three columns with this command but it is not working, any idea?</p>

<pre><code>df['combined']=df.apply(lambda x:'%s_%s' % (x['bar'],x['foo'],x['new']),axis=1)
</code></pre>

<p>I think you are missing one <em>%s</em></p>

<pre><code>df['combined']=df.apply(lambda x:'%s_%s_%s' % (x['bar'],x['foo'],x['new']),axis=1)
</code></pre>

python pandas dataframe