like in RDD, we can also use this method to read multiple files at a time, reading patterns matching files and finally reading all files from a directory. () method is used to read a text file into DataFrame.
2.1 text() – Read text file into DataFrame Note: These methods doens’t take an arugument to specify the number of partitions. Using () and () We can read a single text file, multiple files and all files from a directory into Spark DataFrame and Dataset. Spark read text file into DataFrame and Dataset This complete code is also available at GitHub for reference 2. Val rddWhole:RDD = ("src/main/resources/csv/text01.txt") Val spark:SparkSession = SparkSession.builder() Again, I will leave this to you to explore. You can also read each text file into a separate RDD’s and union all these to create a single RDD. 1.7 Reading all text files separately and union to create a Single RDD I will leave it to you to research and come up with an example. TextFile() and wholeTextFile() returns an error when it finds a nested folder hence, first using scala, Java, Python languages create a file path list by traversing all nested folders and pass all file names with comma separator in order to create a single RDD. #read all text files from a directory to single RDDġ.6 Reading text files from nested directories into Single RDD Println("#read all text files from a directory to single RDD") It also supports reading files and multiple directories combination. #read text files base on wildcard characterġ.5 Read files from multiple directories into single RDD
Val rdd3 = ("src/main/resources/csv/text*.txt") Println("#read text files base on wildcard character") For example below snippet read all files start with text and with the extension “.txt” and creates single RDD. TextFile() and wholeTextFiles() methods also accepts pattern matching and wild characters. This read file text01.txt & text02.txt files.ġ.4 Read all text files matching a pattern Val rdd4 = ("src/main/resources/csv/text01.txt," + Println("#read multiple text files into a RDD") This method also takes the path as an argument and optionally takes a number of partitions as the second argument. SparkContext.wholeTextFiles() reads a text file into PairedRDD of type RDD with the key being the file path and value being contents of the file. #spark read text files from a directory into RDDĬlass .MapPartitionsRDDġ.2 wholeTextFiles() – Read text files into RDD of Tuple. Here, it reads every line in a "text01.txt" file as an element into RDD and prints below output. Val rddFromFile = ("src/main/resources/csv/text01.txt") Println("#spark read text files from a directory into RDD") SparkContext.textFile() method is used to read a text file from HDFS, S3 and any Hadoop supported file system, this method takes the path as an argument and optionally takes a number of partitions as the second argument.
0 kommentar(er)
