pyspark.sql.functions.first¶
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pyspark.sql.functions.first(col, ignorenulls=False)[source]¶ Aggregate function: returns the first value in a group.
The function by default returns the first values it sees. It will return the first non-null value it sees when ignoreNulls is set to true. If all values are null, then null is returned.
New in version 1.3.0.
Notes
The function is non-deterministic because its results depends on the order of the rows which may be non-deterministic after a shuffle.