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

To convert CSV to Pandas DataFrame, use pd read_csv() method.   It will take an external CSV file and convert that file into the DataFrame.   Now, to convert DataFrame to csv , use to_csv() method. ... View more