简单的数据框创建:
df = spark.createDataFrame(
[
(1, "foo"), # create your data here, be consistent in the types.
(2, "bar"),
],
["id", "label"] # add your column names here
)
df.printSchema()
root
|-- id: long (nullable = true)
|-- label: string (nullable = true)
df.show()
+---+-----+
| id|label|
+---+-----+
| 1| foo|
| 2| bar|
+---+-----+
根据官方文档 https://spark.apache.org/docs/latest/api/python/pyspark.sql.html#pyspark.sql.SparkSession.createDataFrame:
- 当模式是列名列表时,将从数据推断每列的类型。(上面的例子↑)
- 当架构为
pyspark.sql.types.DataType
或数据类型字符串,它必须与真实数据匹配。(示例如下↓)
# Example with a datatype string
df = spark.createDataFrame(
[
(1, "foo"), # Add your data here
(2, "bar"),
],
"id int, label string", # add column names and types here
)
# Example with pyspark.sql.types
from pyspark.sql import types as T
df = spark.createDataFrame(
[
(1, "foo"), # Add your data here
(2, "bar"),
],
T.StructType( # Define the whole schema within a StructType
[
T.StructField("id", T.IntegerType(), True),
T.StructField("label", T.StringType(), True),
]
),
)
df.printSchema()
root
|-- id: integer (nullable = true) # type is forced to Int
|-- label: string (nullable = true)
此外,您可以从 Pandas 数据框创建数据框,架构将从 Pandas 数据框的类型推断:
import pandas as pd
import numpy as np
pdf = pd.DataFrame(
{
"col1": [np.random.randint(10) for x in range(10)],
"col2": [np.random.randint(100) for x in range(10)],
}
)
df = spark.createDataFrame(pdf)
df.show()
+----+----+
|col1|col2|
+----+----+
| 6| 4|
| 1| 39|
| 7| 4|
| 7| 95|
| 6| 3|
| 7| 28|
| 2| 26|
| 0| 4|
| 4| 32|
+----+----+