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การเข้าถึงหน้านี้ต้องได้รับการอนุญาต คุณสามารถลอง ลงชื่อเข้าใช้หรือเปลี่ยนไดเรกทอรีได้
การเข้าถึงหน้านี้ต้องได้รับการอนุญาต คุณสามารถลองเปลี่ยนไดเรกทอรีได้
Transforms an array of key-value pair entries (structs with two fields) into a map. The first field of each entry is used as the key and the second field as the value in the resulting map column.
Syntax
from pyspark.sql import functions as sf
sf.map_from_entries(col)
Parameters
| Parameter | Type | Description |
|---|---|---|
col |
pyspark.sql.Column or str |
Name of column or expression |
Returns
pyspark.sql.Column: A map created from the given array of entries.
Examples
Example 1: Basic usage of map_from_entries
from pyspark.sql import functions as sf
df = spark.sql("SELECT array(struct(1, 'a'), struct(2, 'b')) as data")
df.select(sf.map_from_entries(df.data)).show()
+----------------------+
|map_from_entries(data)|
+----------------------+
| {1 -> a, 2 -> b}|
+----------------------+
Example 2: map_from_entries with null values
from pyspark.sql import functions as sf
df = spark.sql("SELECT array(struct(1, null), struct(2, 'b')) as data")
df.select(sf.map_from_entries(df.data)).show()
+----------------------+
|map_from_entries(data)|
+----------------------+
| {1 -> NULL, 2 -> b}|
+----------------------+
Example 3: map_from_entries with a DataFrame
from pyspark.sql import Row, functions as sf
df = spark.createDataFrame([([Row(1, "a"), Row(2, "b")],), ([Row(3, "c")],)], ['data'])
df.select(sf.map_from_entries(df.data)).show()
+----------------------+
|map_from_entries(data)|
+----------------------+
| {1 -> a, 2 -> b}|
| {3 -> c}|
+----------------------+
Example 4: map_from_entries with empty array
from pyspark.sql import functions as sf
from pyspark.sql.types import ArrayType, StringType, IntegerType, StructType, StructField
schema = StructType([
StructField("data", ArrayType(
StructType([
StructField("key", IntegerType()),
StructField("value", StringType())
])
), True)
])
df = spark.createDataFrame([([],)], schema=schema)
df.select(sf.map_from_entries(df.data)).show()
+----------------------+
|map_from_entries(data)|
+----------------------+
| {}|
+----------------------+