How to save an empty data to adlsgen2 using R?

Question

I've explored but didn't find any suggestions. I want to know how to save an empty file to adlsgen2 using R and then read it back to the same code. Thanks for the help.

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score 0 · Answer 1 · answered Jun 02 '22 at 07:05

Since you want to write an empty file to ADLS gen2 using R and read it from that location, first create a dataframe.

The dataframe can either be completely empty, or it can be a dataframe with column names but no rows. You can use the following code to create one.

df <- data.frame()  #OR

df <- data.frame(<col_name>=<type>)

Once you have created a dataframe, you must establish connection to ADLS gen2 account. You can use the method specified in the following link to do that.

https://saketbi.wordpress.com/2019/05/11/how-to-connect-to-adls-gen2-using-sparkr-from-databricks-rstudio-while-integrating-securely-with-azure-key-vault/

After making the connection you can use read and write functions in R language using the path to ADLS gen2 storage. The following link provides numerous functions that can be used according to your requirement.

https://www.geeksforgeeks.org/reading-files-in-r-programming/

score 0 · Answer 2 · edited Jun 05 '22 at 08:41

Sharing the solution to my question:

I've used SparkR to create an empty data frame and save the same in the adls after setting up the spark context.

Solution is below:

Step 1: Create a schema

fcstSchema <- structType(structField("ABC", "string",TRUE))

new_df<- data.frame(ABC=NULL,stringsAsFactors=FALSE)

n<-createDataFrame(new_df,fcstSchema)

SparkR::saveDF(n,path = "abfss://<account_name>@<datalake>.dfs.core.windows.net/<path>/",source = "delta",mode = "overwrite")

How to save an empty data to adlsgen2 using R?

2 Answers2