sum_score = score.reduce(lambda x,y:x+y)这个会执行什么

This code snippet is using PySpark's RDD (Resilient Distributed Datasets) API to calculate the sum of all the values in the `score` RDD.

The `reduce` method is a higher-order function that takes a lambda function as an argument. In this case, the lambda function takes two arguments `x` and `y` and returns their sum `x+y`. The `reduce` method applies this lambda function to pairs of elements in the RDD until all the elements have been aggregated into a single value.

So `sum_score` will contain the sum of all the values in the `score` RDD after the `reduce` operation has been executed.