In order to print the whole value of a column, in scala, you have to set the argument truncate from the show method to false :
maxDf.show(false)
and if you wish to show more than 20 rows, do something like this:
// example showing 30 columns of
// maxDf untruncated
maxDf.show(30, false)
For pyspark, you'll need to specify the argument name :
maxDF.show(truncate = False)