从总和为特定值 pyspark 的数组中提取值

Question

我有一个数据框，它有一个双精度值数组。在数组中，1 或数字的总和等于某个目标值，我想提取等于该值或可以求和等于该值的值。我希望能够在 PySpark 中执行此操作。

| Array                  | Target    | NewArray         |
| -----------------------|-----------|------------------|
| [0.0001,2.5,3.0,0.0031]| 0.0032    | [0.0001,0.0031]  |
| [2.5,1.0,0.5,3.0]      | 3.0       | [2.5, 0.5, 3.0]  |
| [1.0,1.0,1.5,1.0]      | 4.5       | [1.0,1.0,1.5,1.0]|

Answer 1

您可以将逻辑封装为 udf 并基于此创建 NewArray。我借用了从 here.

中识别数组元素总和到目标值的逻辑


from pyspark.sql.types import ArrayType, DoubleType
from pyspark.sql.functions import udf
from decimal import Decimal

data = [([0.0001,2.5,3.0,0.0031], 0.0032),
([2.5, 1.0, 0.5, 3.0], 3.0),
([1.0, 1.0, 1.5, 1.0], 4.5), 
([], 1.0),
(None, 1.0),
([1.0,2.0], None),]


df = spark.createDataFrame(data, ("Array", "Target", ))


@udf(returnType=ArrayType(DoubleType()))
def find_values_summing_to_target(array, target):
    def subset_sum(numbers, target, partial, result):
        s = sum(partial)
        # check if the partial sum is equals to target
        if s == target: 
            result.extend(partial)
        if s >= target:
            return  # if we reach the number why bother to continue
    
        for i in range(len(numbers)):
            n = numbers[i]
            remaining = numbers[i+1:]
            subset_sum(remaining, target, partial + [n], result)
    result = []
    if array is not None and target is not None:
        array = [Decimal(str(a)) for a in array]
        subset_sum(array, Decimal(str(target)), [], result)
        result = [float(r) for r in result]
    return result

df.withColumn("NewArray", find_values_summing_to_target("Array", "Target")).show(200, False)

输出

+--------------------------+------+--------------------+
|Array                     |Target|NewArray            |
+--------------------------+------+--------------------+
|[1.0E-4, 2.5, 3.0, 0.0031]|0.0032|[1.0E-4, 0.0031]    |
|[2.5, 1.0, 0.5, 3.0]      |3.0   |[2.5, 0.5, 3.0]     |
|[1.0, 1.0, 1.5, 1.0]      |4.5   |[1.0, 1.0, 1.5, 1.0]|
|[]                        |1.0   |[]                  |
|null                      |1.0   |[]                  |
|[1.0, 2.0]                |null  |[]                  |
+--------------------------+------+--------------------+

从总和为特定值 pyspark 的数组中提取值

Extract values from an array that sum to a certain value pyspark

arrays

sum

extract

pyspark

输出