計算每個數值欄位對每個群組的最大值。
語法
max(*cols)
參數
| 參數 | 類型 | 說明 |
|---|---|---|
cols |
str | 數據行名稱。 非數字欄位則被忽略。 |
退貨
DataFrame
Examples
df = spark.createDataFrame([
(2, "Alice", 80), (3, "Alice", 100),
(5, "Bob", 120), (10, "Bob", 140)], ["age", "name", "height"])
# Group-by name, and calculate the max of the age in each group.
df.groupBy("name").max("age").sort("name").show()
# +-----+--------+
# | name|max(age)|
# +-----+--------+
# |Alice| 3|
# | Bob| 10|
# +-----+--------+
# Calculate the max of the age and height in all data.
df.groupBy().max("age", "height").show()
# +--------+-----------+
# |max(age)|max(height)|
# +--------+-----------+
# | 10| 140|
# +--------+-----------+