How to properly add a new column using pandas based on two existing columns?
<p>I am totally new to Python (and pandas). I really tried to solve this problem, however, I couldn't solve it without getting the following warning:</p>

<pre><code>A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_indexer,col_indexer] = value instead
</code></pre>

<p>I have two columns containing the <em>first name</em> and <em>last name</em> of a person. What I'm looking for is a way to add a new column to my data frame <em>df</em> containing the <em>full name</em>. This following code worked with warning:</p>

<pre><code>df['Full Name'] = df['First Name'] + " " + df['Last Name']
</code></pre>

<p>Next, I tried</p>

<pre><code>df.loc[:,'Full Name'] = df.loc[:,['First Name']] + " " + df.loc[:,['Last Name']],
</code></pre>

<p>which is invalid. </p>