SparkR (version 2.1.2)

first: Return the first row of a SparkDataFrame

Description

Return the first row of a SparkDataFrame

Aggregate function: returns the first value in a group.

Usage

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

Arguments

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.

Details

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.

See Also

Other SparkDataFrame functions: SparkDataFrame-class, agg, arrange, as.data.frame, attach, cache, coalesce, collect, colnames, coltypes, createOrReplaceTempView, crossJoin, dapplyCollect, dapply, describe, dim, distinct, dropDuplicates, dropna, drop, dtypes, except, explain, filter, gapplyCollect, gapply, getNumPartitions, group_by, head, histogram, insertInto, intersect, isLocal, join, limit, merge, mutate, ncol, nrow, persist, printSchema, randomSplit, rbind, registerTempTable, rename, repartition, sample, saveAsTable, schema, selectExpr, select, showDF, show, storageLevel, str, subset, take, union, unpersist, withColumn, with, write.df, write.jdbc, write.json, write.orc, write.parquet, 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

Examples

# NOT RUN {
sparkR.session()
path <- "path/to/file.json"
df <- read.json(path)
first(df)
# }
# NOT RUN {
first(df$c)
first(df$c, TRUE)
# }