| 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)