first {SparkR} | R Documentation |
Aggregate function: returns the first value in a group.
first(x, ...) ## S4 method for signature 'SparkDataFrame' first(x) ## S4 method for signature 'characterOrColumn' first(x, na.rm = FALSE)
x |
a SparkDataFrame or a column used in aggregation function. |
... |
further arguments to be passed to or from other methods. |
na.rm |
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.
first(SparkDataFrame) since 1.4.0
first(characterOrColumn) since 1.4.0
Other SparkDataFrame functions: SparkDataFrame-class
,
agg
, arrange
,
as.data.frame
,
attach,SparkDataFrame-method
,
cache
, checkpoint
,
coalesce
, collect
,
colnames
, coltypes
,
createOrReplaceTempView
,
crossJoin
, dapplyCollect
,
dapply
, describe
,
dim
, distinct
,
dropDuplicates
, dropna
,
drop
, dtypes
,
except
, explain
,
filter
, gapplyCollect
,
gapply
, getNumPartitions
,
group_by
, head
,
hint
, histogram
,
insertInto
, intersect
,
isLocal
, isStreaming
,
join
, limit
,
merge
, mutate
,
ncol
, nrow
,
persist
, printSchema
,
randomSplit
, rbind
,
registerTempTable
, rename
,
repartition
, sample
,
saveAsTable
, schema
,
selectExpr
, select
,
showDF
, show
,
storageLevel
, str
,
subset
, take
,
toJSON
, union
,
unpersist
, withColumn
,
with
, write.df
,
write.jdbc
, write.json
,
write.orc
, write.parquet
,
write.stream
, write.text
Other agg_funcs: agg
, avg
,
countDistinct
, count
,
kurtosis
, last
,
max
, mean
, min
,
sd
, skewness
,
stddev_pop
, stddev_samp
,
sumDistinct
, sum
,
var_pop
, var_samp
,
var
## 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)