you can check if the value exists by using distinct before you loop over
the dataset.
man. 1. mai 2023 kl. 10:38 skrev marc nicole <mk1853...@gmail.com>:
> Hello
>
> I want to change values of a column in a dataset according to a mapping
> list that maps original values of that column to other new values. Each
> element of the list (colMappingValues) is a string that separates the
> original values from the new values using a ";".
>
> So for a given column (in the following example colName), I do the
> following processing to alter the column values as described:
>
> for (i=0;i<colMappingValues.size();i++){
>>
>> //below lists contains all distinct values of a column
>> (colMappingValues[i]) and their target values)
>> allValuesChanges = colMappingValues[i].toString().split(";", 2);
>>
>> dataset = dataset.withColumn(colName,
>> when(dataset.col(colName).equalTo(allValuesChanges[0])),allValuesChanges[1]).otherwise(dataset.col(colName));
>
> }
>
> which is working but I want it to be efficient to avoid unnecessary
> iterations. Meaning that I want when the column doesn't contain the value
> from the list, the call to withColumn() gets ignored.
> How to do exactly that in a more efficient way using Spark in Java?
>
>
>
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