builder.getOrCreate() 1.创建DataFrame 可以使用pyspark.sql.SparkSession.createDataFrame方法创建一个PySpark DataFrame,通常通过传递一个列表、元组、字典和pyspark.sql.Rows的列表,一个pandas DataFrame或一个由此类列表组成的RDD来实现。pyspark.sql.SparkSession.createDataFrame方法可以通过scheme参数指定DataFrame的模式...
spark = SparkSession.builder.appName("MaxDate").getOrCreate() 加载数据集并创建DataFrame: 代码语言:txt 复制 data = [("group1", "2022-01-01"), ("group1", "2022-02-01"), ("group2", "2022-03-01"), ("group2", "2022-04-01"), ("group2", "2022-05-01")] df = spark....
In this code snippet, we first create a DataFramedfwith a “timestamp” column of type StringType. We then use theto_date()function to convert the timestamps to dates, followed by using thecast()function to change the data type to DateType. name In conclusion, changing data types in ...
sql(sql_create)DataFrame[] 构造日期'{dt}'和热搜类型{num}两个参数 # sql写入临时表 sql_insert = ''' insert overwrite table temp.loop_write_example partition (point_date = '{dt}',dtype={num}) select sum(if(dt between date_add('{dt}',-{num}) and '{dt}',cnt,null)) as cnt ...
itertuples(): 按行遍历，将DataFrame的每一行迭代为元祖，可以通过row[name]对元素进行访问，比iterrows...
df = hc.createDataFrame(sc.parallelize([['a', [1,2,3]], ['b', [2,3,4]]]), ["key", "value"]) df.printSchema() df.show() root |-- key: string (nullable = true) |-- value: array (nullable = true) | |-- element: long (containsNull = true) ...
Advanced DataFrame Operations Handling missing values (fillna(), dropna()) Using agg() for aggregations Joining datasets (join(), union(), merge()) Data Cleaning & Transformation: Working with dates and timestamps Regular expressions in PySpark User-defined functions (UDFs) and performance consider...
hive> create database crime; hive> use crime; hive> create external table log( Dates string, Category string, Descript String, PdDistrict string, Resolution string, Address String, X string, Y string)row format delimited fields terminate by ‘,’stored as textfile location ‘/spark’; ...
Create your first DataFrame: from pyspark.sql import SparkSession spark = SparkSession.builder.getOrCreate() # I/O options: https://spark.apache.org/docs/latest/api/python/reference/pyspark.sql/io.html df = spark.read.csv('/path/to/your/input/file') Basics # Show a preview df.show()...
Managing Tables- DML and Create Partitioned Tables usingSpark SQL Overview ofSpark SQL Functions to manipulate strings, dates, null values, etc Windowing Functions using Spark SQL for ranking, advanced aggregations, etc. Data Engineering using Spark Data Frame APIs ...