Aggregate function: returns the first value in a group.
Usagefirst(x, ...)
# S4 method for class 'SparkDataFrame'
first(x)
# S4 method for class 'characterOrColumn'
first(x, na.rm = FALSE)
Arguments
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 the order of the rows which may be non-deterministic after a shuffle.
Notefirst(SparkDataFrame) since 1.4.0
first(characterOrColumn) since 1.4.0
See alsoOther SparkDataFrame functions: SparkDataFrame-class
, agg()
, alias()
, arrange()
, as.data.frame()
, 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()
, unionAll()
, unionByName()
, union()
, unpersist()
, unpivot()
, withColumn()
, withWatermark()
, with()
, write.df()
, write.jdbc()
, write.json()
, write.orc()
, write.parquet()
, write.stream()
, write.text()
Other aggregate functions: avg()
, column_aggregate_functions
, corr()
, count()
, cov()
, last()
if (FALSE) { # \dontrun{
sparkR.session()
path <- "path/to/file.json"
df <- read.json(path)
first(df)
} # }
if (FALSE) { # \dontrun{
first(df$c)
first(df$c, TRUE)
} # }
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4