To save a DataFrame as a text file in PySpark, you need to convert it to an RDD first, or use DataFrame writer functions. Using DataFrame writer: df.write.format("text").save("path_to_output_directory") Converting to RDD and then using saveAsTextFile rdd = df.rdd.map(lambda row: str(row)) rdd.saveAsTextFile("path_to_output_directory") ... View more

To append data frames in R, use the rbind() function. The rbind() is a built-in R function that can combine several vectors, matrices, and/or data frames by rows.   When it comes to appending data frames, the rbind() and cbind() function comes to mind because they can concatenate the data frames horizontally and vertically. In this example, we will see how to use the rbind() function to append data frames. ... View more

To check null in JavaScript, use triple equals operator(===) or Object is() method. If you want to use Object.is() method then you two arguments.   1)  Pass your variable value with a null value. 2) The null value itself.   To find the difference between null and undefined, use the triple equality operator or Object is() method.   To loosely check if the variable is null, use a double equality operator(==). The double equality operator can not tell the difference between null and undefined, so it counts as same. So if you want to strict check, then don't use a double equality operator. It will lead to misconclusion. ... View more