title: Horizontal concatenation in Pyspark
body: <p>is there an equivalent on pyspark that allow me to do similar operation as in Pandas</p>
  <pre><code>pd.contact(df1, df2, Axis=1)
  </code></pre>
  <p>I have tried several methods so far none of them seems to work. the concatenation that it does is vertical, and I'm needing to concatenate multiple spark dataframes into 1 whole dataframe.</p>
  <p>if I use union or unionAll it the dataframes get stacked vertically, as one single column which is not useful for my use case. I also have tried this example (did not work either):</p>
  <pre><code>from functools import reduce  
  from pyspark.sql import DataFrame
  
  def unionAll(*dfs):
       return reduce(DataFrame.unionAll, dfs) 
  </code></pre>
  <p>any help will be greatly appreciated.</p>