first {SparkR}R Documentation

Return the first row of a SparkDataFrame


Aggregate function: returns the first value in a group.


first(x, ...)

## S4 method for signature 'SparkDataFrame'

## S4 method for signature 'characterOrColumn'
first(x, na.rm = FALSE)



a SparkDataFrame or a column used in aggregation function.


further arguments to be passed to or from other methods.


a logical value indicating whether NA values should be stripped before the computation proceeds.


The function by default returns the first values it sees. It will return the first non-missing value it sees when na.rm is set to true. If all values are missing, then NA is returned. Note: the function is non-deterministic because its results depends on order of rows which may be non-deterministic after a shuffle.


first(SparkDataFrame) since 1.4.0

first(characterOrColumn) since 1.4.0

See Also

Other SparkDataFrame functions: SparkDataFrame-class, agg, alias, arrange,, attach,SparkDataFrame-method, broadcast, cache, checkpoint, coalesce, collect, colnames, coltypes, createOrReplaceTempView, crossJoin, cube, dapplyCollect, dapply, describe, dim, distinct, dropDuplicates, dropna, drop, dtypes, exceptAll, except, explain, filter, gapplyCollect, gapply, getNumPartitions, group_by, head, hint, histogram, insertInto, intersectAll, intersect, isLocal, isStreaming, join, limit, localCheckpoint, merge, mutate, ncol, nrow, persist, printSchema, randomSplit, rbind, rename, repartitionByRange, repartition, rollup, sample, saveAsTable, schema, selectExpr, select, showDF, show, storageLevel, str, subset, summary, take, toJSON, unionByName, union, unpersist, withColumn, withWatermark, with, write.df, write.jdbc, write.json, write.orc, write.parquet,, write.text

Other aggregate functions: avg, column_aggregate_functions, corr, count, cov, last


## Not run: 
##D sparkR.session()
##D path <- "path/to/file.json"
##D df <- read.json(path)
##D first(df)
## End(Not run)
## Not run: 
##D first(df$c)
##D first(df$c, TRUE)
## End(Not run)

[Package SparkR version 2.4.0 Index]