--- 2.3 过滤数据--- 3、--- 合并 join / union --- 3.1 横向拼接rbind --- 3.2 Join根据条件 --- 单字段Join 多字段join 混合字段 --- 3.2 求并集、交集 --- --- 3.3 分割:行转列 --- 4 --- 统计 --- --- 4.1 频数统计与筛选 --- --- 4.2 分组统计--- 交叉分析 **groupBy方法...
# SparkSQL的许多功能封装在SparkSession的方法接口中,SparkContext则不行的。 spark=SparkSession.builder \.appName("sam_SamShare")\.config("master","local[4]")\.enableHiveSupport()\.getOrCreate()sc=spark.sparkContext # 创建一个SparkDataFrame rdd=sc.parallelize([("Sam",28,88,"M"),("Flora"...
df[df.col==?] df.filter(condition) df.where(condition) # 计数 df.count() # 自定义函数 udffunc = udf(func, StringType()) df.withColumn('col', udffunc(df.col)) ## 数据关联 df.join(df2, condition, how='inner') ## 排序 df.orderBy(col, F.desc(col)) 1. 2. 3. 4. 5. 6....
withReplacement = True or False代表是否有放回。 fraction = x, where x = .5,代表抽取百分比 — 1.5 按条件筛选when / between — when(condition, value1).otherwise(value2)联合使用: 那么:当满足条件condition的指赋值为values1,不满足条件的则赋值为values2. otherwise表示,不满足条件的情况下,应该赋值...
join(address, on="customer_id", how="left") - Example with multiple columns to join on dataset_c = dataset_a.join(dataset_b, on=["customer_id", "territory", "product"], how="inner") 8. Grouping by # Example import pyspark.sql.functions as F aggregated_calls = calls.groupBy("...
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join:相当于SQL中的内连接,返回两个RDD以key作为连接条件的内连接。 2. 行动 行动操作会返回结果或将RDD数据写入存储系统,是触发Spark启动计算的动因。行动操作包括foreach、collect等。下面对常用的行动操作进行介绍。 foreach:对RDD中每个元素都调用用户自定义函数操作,返回Unit。
spark.sql('select * from Iris left join Plant on Iris.Species=Plant.lei') 创建临时视图 临时视图的生命周期与此Spark应用程序相关联,断连之后,临时数据会自动清除; sdf.createOrReplaceTempView('Iris_tmp') # 对临时视图按照sql的方式进行操作
To join on multiple conditions, use boolean operators such as & and | to specify AND and OR, respectively. The following example adds an additional condition, filtering to just the rows that have o_totalprice greater than 500,000:Python Kopiraj ...
Presto allows querying data where it lives, includingApache Hive,Thrift,Kafka,Kudu, andCassandra,Elasticsearch, andMongoDB. In fact, there are currently 24 different Prestodata source connectorsavailable. With Presto, we can write queries that join multiple disparate data sources, without moving the ...