pyspark dataframe Column alias 重命名列(name) df = spark.createDataFrame( [(2, "Alice"), (5, "Bob")], ["age", "name"])df.select(df.age.alias("age2")).show()+----+|age2|+----+| 2|| 5|+----+ astype alias cast 修改列类型
Before diving into PySpark SQL Join illustrations, let’s initiate “emp” and “dept” DataFrames.The emp DataFrame contains the “emp_id” column with unique values, while the dept DataFrame contains the “dept_id” column with unique values. Additionally, the “emp_dept_id” from “emp”...
上述示例对 dataframe 的 query 列的字符串做首尾空格去除操作,完整示例代码如下: from pyspark.sql import SparkSession from pyspark.sql.functions import regexp_replace spark_session = SparkSession.builder \ .appName('knowledgedict-dataframe') \ .master('local') \ .getOrCreate() df = spark_sessi...
df = spark.createDataFrame([{'name':'Alice','age':1}, {'name':'Polo','age':1}]) 4.指定schema创建DataFrame schema = StructType([ StructField("id", LongType(), True), StructField("name", StringType(), True), StructField("age", LongType(), True), StructField("eyeColor", Stri...
根据条件对DataFrame进行过滤 where(condition)和filter(condition)是同一个函数 (1.3版本新增) 1. 2. 3. 参数: condition ——– 一个由types.BooleanType组成的Column对象,或一个内容为SQL表达式的字符串 >>> df.filter(df.age > 3).collect() [Row(age=5, name=u'Bob')] >>> df.where(df.age =...
df = spark.createDataFrame(data).toDF(*columns) 2. PySpark alias Column Name pyspark.sql.Column.alias()returns the aliased with a new name or names. This method is the SQL equivalent of theaskeyword used to provide a different column name on the SQL result. ...
pyspark.sql.DataFrame: 是Spark SQL的主要抽象对象,若干行的分布式数据,每一行都要若干个有名字的列。 跟R/Python中的DataFrame 相像,有着更丰富的优化。DataFrame可以有很多种方式进行构造,例如: 结构化数据文件,Hive的table, 外部数据库,RDD。 pyspark.sql.Column DataFrame 的列表达. pyspark.sql.Row DataFrame的...
Parameters: col1 - The name of the first column col2- The name of the second column New in version 1.4. createOrReplaceTempView(name) 根据dataframe创建或者替代一个临时视图 这个视图的生命周期是由创建这个dataframe的SparkSession决定的 >>> df.createOrReplaceTempView("people")>>> df2 = df.filter...
python—向Dataframepyspark中的连接列添加行号# check length of base string and subtract from max ...
appName('sql'). \ master('local'). \ getOrCreate() df = spark.read.json("file:///home/pyspark/test.json") df.show() # 关闭spark会话 spark.stop() 测试记录: 1.1.2 通过CSV文件创建DataFrame csv测试文件: 代码: #!/usr/bin/env python# -*- coding: utf-8 -*-frompyspark.sqlimport...