הערה
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Important
This feature is in Public Preview.
Returns the 1-based n-th point of the input linestring, or None if it doesn't exist.
For the corresponding Databricks SQL function, see st_pointn function.
Syntax
from pyspark.databricks.sql import functions as dbf
dbf.st_pointn(col1=<col1>, col2=<col2>)
Parameters
| Parameter | Type | Description |
|---|---|---|
col1 |
pyspark.sql.Column or str |
A Geography or Geometry value representing a linestring. |
col2 |
pyspark.sql.Column or int |
A 1-based position in the linestring indicating the point that should be returned. |
Examples
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([('LINESTRING(1 2,3 4,5 6)',)], ['wkt'])
df.select(dbf.st_asewkt(dbf.st_pointn(dbf.st_geogfromtext('wkt'), 3)).alias('result')).collect()
[Row(result='SRID=4326;POINT(5 6)')]
from pyspark.databricks.sql import functions as dbf
df = spark.createDataFrame([('LINESTRING ZM (1 2 3 4,5 6 7 8)',)], ['wkt'])
df.select(dbf.st_asewkt(dbf.st_pointn(dbf.st_geomfromtext('wkt', 4326), -2)).alias('result')).collect()
[Row(result='SRID=4326;POINT ZM (1 2 3 4)')]