title: How to transform an array of array to a simple array?
body: <p>I am trying to concatenate columns of different type to create my dataframe but each obtained element of the Dataframe was like this:</p>
  
  <p><code>[[259200.0] [259200.0] [259200.0]..., [260099.98] [260099.98] [260099.98]]</code></p>
  
  <p>Means if my DF is a matrix so each DF[i,j] is like the above code.</p>
  
  <p>But I want to get a single array of all the sub-arrays like below: </p>
  
  <p><code>[259200.0 259200.0 259200.0 ... 260099.98 260099.98 260099.98]</code></p>
  
  <p>I will add the pic to clarify more my point :</p>
  
  <p><a href="https://i.stack.imgur.com/hFE6I.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hFE6I.png" alt="Here is my final DF"></a></p>
  
  <p>In fact I am creating this table through the next line :</p>
  
  <pre><code>  `features2[i]=pd.DataFrame([[label[i], max[i], mean[i], Cost[1:]])#
     mydataset1=pd.concat([mydataset1,features2[i]], axis=0)`
  </code></pre>
  
  <p>The Cost is already a Table with 140 columns and I want to concatenate it to the other three columns so at the end I will get a DF with 143 columns and N rows</p>