如何通过在 for 循环中更新其列值来更新数据集？

Question

I want to loop over a list of columns and if a certain condition is satisfied then i want to change the value of the current column with NaN , but with what i have tried (below) i override with previous dataset instead of updating the last dataset satisfying the condition:

for (String att: listAtts) {
           datasetInit = ...
            resDf = datasetInit;
            if (condition) {
                resDf = resDf.withColumn(att,lit("NaN"));
...

My problem here is that for each iteration resDf takes datasetInit which erase the last resDf update. How to achieve that in JAVA?

Thanks

Answer 1

I solved it using the following:

...
if (resDf.count == 0)
  resDf = datasetInit;
...

To Not assign the datasetInit if resDf has at least been updated once