Scala read file to string

I am stuck at a point where I need to read the Array [String] using Scala's. // to specify in detail how the write should take place. apache. I could come up with the following solution, which almost works, the only problem is that the newlines are removed: val fileAsFilteredString = io Jan 10, 2014 · I'm new to Scala. map { xs => (xs. txt' on ALL executer nodes. config. beans. read(path) To read the file as line at a time, substitute os. Scala doesn’t offer any special conveniences for reading or writing binary files, so either use a) the Apache Commons IO library, or b) the Java FileInputStream and FileOutputStream classes. Here is what I got: val pre:String = " <value enum=\"" val mid:String = "\" There are several ways to read command-line input, but the easiest way is to use the readLine method in the scala. Dec 2, 2014 · 1. May 1, 2015 · And using IOUtils. txt") . The textFile method reads a file as a collection of lines. copy to copy the same data from one file to another takes 0. conf. Solution. For example, to represent a pet owner with the name of its pets, you can. txt") Feb 8, 2017 · I am creating a spark scala code in which I am reading a continuous stream from MQTT server. Dec 30, 2016 · 0. Example: Console. I don't know what happens to that string when you're done reading it in. 5 seconds, processing takes 0. temp. libs. 13, BeanProperty can now be found as scala. Below is how I approached it: I saved an Array[String] to a Parquet file from Spark. fromInputStream(is). This results in an RDD[(String, String)] where . _2. As a complete beginner in the language, I wanted to make sure to find the right way to do it, e. I want to extract each word, remove the white spaces, convert all to lowercase and call them based on the index of each word. To read and write Scala objects to and from JSON files, you can use uPickle and OS-Lib as follows: Scala 2. fromFile(). p12 format API key from /resources, writes it to /tmp, and then uses the file path string as an input to a spark-google-spreadsheets write. Can any one help. Nov 8, 2022 · You want to process the lines in a CSV file in Scala, either handling one line at a time or storing them in a two-dimensional array. Let’s create a YAML string with a sample configuration: val ordersYamlConfig: String =. Oct 3, 2012 · Encoding and decoding happens in the IO classes. You want to write plain text to a file in Scala, such as a simple configuration file, text data file, or other plain-text document. mkString val json_data = JSON. res0: Int = 42. txt") You can also use various options to control the CSV parsing, e. reverse. _. Mar 3, 2021 · Is there a way to read a file as byte array in spark? As of now I am using the below code, but the content of the file changing in byte level. txt" )) writer. The goal is to count the number of unique substrings/words in the given string (which is the entire file). Read entire file in Scala? Jul 16, 2021 · The source code to read data from a text file is given below. {BufferedOutputStream, FileOutputStream} val fs = FileSyste The following steps can be summarized like this, if we omit steps of writing and reading text files, //1. We can read data from the file using the Source object that is returned by this method. _, you can use an instance of PrintWriter to write to a file. map(lambda x: (x[0], ' '. Load the file in pure Scala (not Spark) and then use sc. // an existing file with the new data. I see lot of question on the same topic, but none provide a satisfactory answer. As such, saving a text file shouldn't need to be done by "Spark" (ie, it shouldn't be done in distributed spark jobs, by workers). val path: os. 1, “How to Open and Read a Text File in Scala” with Recipe 1. fromFile(file)) } Note that this won't fetch files in sub-directories, doesn't have more advance Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand May 27, 2017 · How to read the file into a Map where the values occur over multiple lines ? But some of mappings values are over multiple lines : such as : k -> v \n test \n here k2 -> v2 Sep 21, 2017 · My requirement is that I need to read line by line and split it on particular delimiter and extract values to put in respective columns in different file. val a = scala. I want to read each of the file and build a List of RDD containining the content of each files. val rightList: List[Int] = pair. Scala 3. Copy the data file on all the executer nodes. Then we can slurp the entire file into a string with os. convert(someJSON) I've spent quite a bit of time looking at the Spark API, and the best I can find is to use a sqlContext like so: var someJSON : String = getJSONSomehow() Jun 2, 2016 · This sounds like storing simple application/execution metadata. I will be receiving stream of data after every 1 second. I have a XML file that I'm trying to process through Spark-Shell using Scala. Path = os. Use a slightly longer approach that properly closes the file. So most of the stuff I found (also on SO ) recommends I use io. NumberFormatException: For input string: "42a". join(list(x[1])))). – Jun 1, 2016 · Here is a complete example of parsing your input JSON to a regular Scala case class: import play. 000999, 01/01/2019, Suresh, abc 2019-01-02 22:11:11. I'm trying to read an in-memory JSON string into a Spark DataFrame on the fly: var someJSON : String = getJSONSomehow() val someDF : DataFrame = magic. bufferedSource. listFiles. getLines(), but what I want is like I. parseFull(json_content) // go on from there Mar 18, 2024 · Circe is a Scala library that simplifies working with JSON, allowing us to easily decode a JSON string into a Scala object or convert a Scala object to JSON. The line separator can be changed as shown in the example Jul 16, 2015 · The code is working fine but the only issue is I am giving the absolute path when reading the text file. So, if my file has 10 lines, I have ten lists. spark: SparkSession = // create the Spark Session val df = spark. os. scala scala ConsoleReader Reading File Content. When the end of file is reached a -1 value is returned by the read method, so that’s why the takeWhile method is used as shown. (From comments) This is my code so far: final JavaRDD<String> File = sc. Following is the example which shows you how to read from “Demo. Sep 21, 2016 · 10. _1. After importing java. readLine. I was trying to parse a Yaml File using snakeyaml in scala. val source = Source. Mar 10, 2015 · Best way would be to use a . I know it's kind of preposterous. toByte)) // another option for write is openOptions which allows the caller. /scala_input. We’ve explored both options — first holding the file as a String literal or reading the file in from the file system directly — and we know when either option is most appropriate to use. In the previous examples we used str to type a JSON value as a string. csv("file. To demonstrate how this works, let’s create a little example. fromFile(fname) Or, if you think the class name is too long, import the class first: import scala. csv file to scala while preserving some of the structure. 4. make it RDD and get its schema, then convert it to JSON val p2 = sc. , YARN in case of using AWS EMR) to read the file directly. select("wantedCol"). In Scala, you can use a case class to define your own data type. I want to save and append this stream in a single text file in HDFS. readInt() println("The value of a is " + a) similarly. txt, you can use below code: val writer = new PrintWriter(new File("test. I don't know why : (. csv Defining the schema as String Jun 25, 2016 · That's all I can think of based on the code you posted. 2, “How to write text files in Scala. How to parse string to array in Spark? 1. import upickle. The result would only contain lines where the second element of each line is either Bob, Tom, or Fred. I also noticed that reading file takes 1. txt". val configPath = System. May 11, 2021 · hope this helps, it's wotking fine for me with your A. There are two primary ways to open and read a text file: Use a concise, one-line syntax. Just use Source. parseFull expects a JSON String, not a path to a file containing such a String. toList //2. spark. builder. fromFile ("Sample. Config, ConfigFactory } // this can be set into the JVM environment variables, you can easily find it on google. _ case class PetOwner(name: String, pets: List[String]) implicit val ownerRw: ReadWriter [ PetOwner] = macroRW. How can I convert RDD[String] to a DataFrame Mar 30, 2017 · In this case you start with two empty Lists stored as Tuple an on each step you prepend the first element of the array to the first List, and the second element to the second List. Since the RDD contains strings it needs to first be converted to tuples representing the columns in the dataframe. mkString("\n") does pretty much the same thing. So I need this data to be appended in single text file in HDFS. textFile("source_file") fileRead: org. Following is the directory structure of my project. It can read a file from the local filesystem, or from a Hadoop or Amazon S3 filesystem using "hdfs://" and "s3a://" URLs, respectively. parallelize(p1) val p3 = spark. Spark SQL provides spark. textFile. I am having a Zipped file containing multiple text files. groupByKey(). Aug 19, 2017 · Ask questions, find answers and collaborate at work with Stack Overflow for Teams. Apr 22, 2017 · 2. Now, while doing this or after doing this, I want to add all the lists into an Array. close. pair => new String(pair. 04 operating system successfully. pwd Feb 3, 2024 · 6. e. 12 and 2. I’ll show those classes in this recipe. def readBoolean(): Boolean Jan 11, 2016 · I want to perform some operations on particular data in a CSV record. Text Files. default. Nov 30, 2017 · Assuming that your text file is a CSV file, you can use following code for reading a CSV file in a Dataframe where spark is the SparkSession: val df = spark. So - you should first load the file and then parse it: val input_file = ". write(path, "hello\nthere\n" ) println(os. map (file => io. 6 seconds, and writing takes 2. read target column as List of String val p1 = df. 6, you can simply use the built-in csv data source:. conf file and the ConfigFactory instead of having to do all the file parsing by yourself: import java. Oct 29, 2018 · I have a one text file with following format. json" val json_content = scala. Mar 7, 2016 · The shown text is what I get after I using val file = Source. Reading Scala File from Console. toInt. We use its companion object to read files. StdIn . val leftList: List[Int] = pair. At the end you will have to Lists with the columns in reverse order*/. In Scala 2. 1. implicits. Scala: Read file as infinite/async stream of lines. getLines as you already stated. textFile(Filename). (You can always define your own shortcuts, of course: def gis(s: String) = new GZIPInputStream(new BufferedInputStream(new FileInputStream(s))) is barely longer than what you've typed already, and now Java 11 added the readString () method to read small files as a String, preserving line terminators: String content = Files. Conclusion. You should look at the documentation of the scala. json. For example, to write string "Hello" to a file named test. I am new to Scala and I need to read the contents of a text file into a string while removing certain lines at the same time. getName). import org. May 2, 2018 · To use this functionality, first import the spark implicits using the SparkSession object: val spark: SparkSession = SparkSession. Works like a breeze! – Reading a file. Its an encrypted file, so looking for ways to read the file without any change in byte level. collect() Jul 13, 2011 · For Scala < 2. One more approach, using grouped, which takes into account a (possibly) uneven number of lines, Source. Take a a look at scala. StdIn. Nov 23, 2010 · 77. Dec 15, 2023 · 7. Code: scala> Console. getLength, charset) Jun 27, 2024 · When reading JSON files in Scala we follow these steps: Opening the file for reading using Scala’s Source. Configuration; import org. rdd. Oct 21, 2016 · JSON. getLines()) yield line). Jan 24, 2013 · I have read the entire text of a 100+ M. read(os. read. Your data file needs to exist in 'home/spark/data. // read a PetOwner from a JSON file val petOwner: PetOwner = read[ PetOwner ](os. Hmm, so I tried using Source. reverse) } Note that getLines gives an iterator for fetching one line at a time, sequentially, then grouped gives yet another iterator with paired lines for Sep 10, 2015 · The problem with split(",") is that when you come across a string like "This, that", Reading in a . RDD[String] = source_file MapPartitionsRDD[8] at textFile at <console>:21. Supposing we have the path to a file: Scala 2 and 3. fromFile . write(). readline method is used to read it from console. write("Hello") writer. file. Jun 25, 2024 · This is an excerpt from the 1st Edition of the Scala Cookbook (partially modified for the internet). server: host: localhost. import com. To read it I use: scala/spark:Read in RDD[(String,Int)] 3. // Scala program to read data from a text file import scala. Mar 1, 2016 · I'm working with Scala in IntelliJ IDEA 15 and trying to parse a large twitter record json file and count the total number of hashtags. 2. So, I have an Array of Lists, without using "var", so essentially just 'val'. matching. It this case I can't start writing before all lines are processed, but processing and reading could be done atleast partially in parallel. The toInt method will throw an Exception in case of an incorrect number format: scala> "42a" . To read the CSV file I use opencsv. json(spark. From documentation of endsWith method: Read and process files in scala. fromFile("file. ScalaDex CSV Search. The key of the Map should be the label (this in the first column) and the Map values should be the other values (these one in the rest of the columns). {. To use it, you need to first import it, like this: import scala. @Brian could you see the EDIT in my question. Just in case if some one is interested in schema definition as simple string with date and time stamp. csv: Feb 3, 2021 · Solution. case class MyJson(Received: String, Created: String, Location: Option[Location], Infos: Option[List[String]], DigitalInputs: Option[List[DigitalInputs]]) case class Location(Created: String, Coordinate: Coordinate) In Scala, reading from and writing to files on file-system is very easy. Apr 20, 2023 · 1. api. Regex) = {. apa Reading text files. Json. getBytes, 0, pair. name: Orders String. collect. Here is a link to the ScalaDex search results for CSV. So I gave myself 90 minutes to goof around and try a few different ways to write a simple “line count” program in Scala. You can refer to Reading file in different formats. filter(file => regex. Scanner. sparkContext. ): Spark_Full. mkString to convert my text into UTF-8, but that didn't scalac ConsoleReader. readAllBytes(Paths. getOrCreate() import spark. new java. case class PetOwner(name: String, pets: List[String]) To be able to write a PetOwner to JSON we need to provide a ReadWriter instance for the case class PetOwner . File(dir). wholeTextFiles (sc is a SparkContext in this case). In this article, we have learned how to read in a CSV using the Akka-streams framework. hadoop. get the encoding right. First, read the File as usual: val df = spark. To convert between a String and an Int there are two options. Source object, which contains factory methods for creating Source s, which take the encoding as a parameter. That being said, you wouldn't be using the Spark API Nov 28, 2015 · Reading a text file in scala, one line after the other, not iterated. _1 is the file name, and . last. txt file in to the resources directory, if so still how would I read that file?) Apr 21, 2016 · Update - as of Spark 1. available, read the whole thing into a byte array, and create a string from that directly. read: Scala 2 and 3. Below is my input sample data: Serializing a custom object to JSON. write (Array (1,2,3) map ( _. I'm trying to read a CSV file and convert it to RDD. read(). com Jun 30, 2016 · I did new String(Files. 12 seconds (even faster than using NIO), so the file system isn't the bottleneck. Similar methods exist for other types of values, namely: num for numeric values, returning Double; bool for boolean values, returning Boolean; arr for arrays, returning a mutable Buffer[ujson. To demonstrate those classes, the following code is a close Scala translation of the CopyBytes class Aug 21, 2019 · 1. How can I read a file from HDFS using Scala (not using Spark)? When I googled it I only found writing option to HDFS. A bit rough on the edges, but maybe something like : def getFilesMatchingRegex(dir: String, regex: util. Unless you want to read file locally, using standard IO tools (Read entire file in Scala?) and parallelize there isn't. This is the class Source. The library automatically generates the object encoders and decoders, thereby reducing the lines of code we need to work with JSON in Scala. Dec 8, 2014 · For Scala 2. Reading From a YAML String. wholeTextFiles. 6, “How to read a YAML configuration file in Scala. the file i am using is "abcd. If you can assume the stream's nonblocking, you could just use . Apr 19, 2018 · No, if you read a non UTF-8 format file in UTF-8 mode, non-ascii characters will not be decoded properly. getLines. The code is as follows: Jun 16, 2015 · I tried to convert a scala string to array by splitting it by ,. The ideal place for you to put it is in your driver code, typically after constructing your RDDs. Source. g. io. text("path") to write to a text file. BeanProperty. I am very new to Scala and the idea of functional programming. So "if line 1, column 2 contains "Bob" or "Tom" or "Fred", then return that line. createDataset(p2)) val p4 Sep 29, 2022 · As shown in the following ScalaTest tests, you can test the getLinesUppercased method by passing it either a Source from a file or a String: var source: Source = _. You need to read a YAML configuration file in a Scala application. root / "usr" / "share" / "dict" / "words". fromFile(args(0)). All samples I've found online want to read/buffer the entire file into a list or array and then access the individual lines from that construct. However, after trying it out like so, reading a UTF-8 file: val user_list = Source Dec 24, 2011 · @NickCecil Your filter for text files does not work as you intended. Dec 4, 2020 · This example uses some proposed Scala 3 (Dotty) significant indentation syntax, but it’s easily converted to Scala 2. 7. fromFile(input_file). First, we can use the toInt method: scala> "42" . text("file_name") to read a file or directory of text files into a Spark DataFrame, and dataframe. My further operations are based on the heading provided in CSV file. readString(path, encoding); For versions between Java 7 and 11, here's a compact, robust idiom, wrapped up in a utility method: static String readFile(String path, Charset encoding) Jan 8, 2020 · I'm pretty much new to Scala. B file onto memory (into a string) and have to process it (I believe processing large text files is a common task in Natural Language Processing). When reading a text file, each line becomes each row that has string “value” column by default. size) // prints: 2. Below is the code I am currently using. // By default the file write will replace. GraalVM. toLowerCase. cache(); Nov 17, 2012 · I'm reading a file line by line and putting into a list. . This is Recipe 12. Nov 2, 2010 · 2. 11, if getLines doesn't do exactly what you want you can also copy the a file out of the jar to the local file system. Value] obj for objects, returning a mutable Map[String, ujson. . _2 is the entire file content. lang. Update. isDefined) . fromFile (filePath); We can read data from the Source object Using the mkString method we can read the entire Jan 18, 2019 · I have a string which I want to override and write a an hdfs text file in Scala. """. The main problem seems to be that the complete type of the parse result mirrors the structur Apr 13, 2015 · I'm trying to use basic Java code in Scala to read from a file and write to an OutputStream, but when I use the usual while( != -1 ) in Scala gives me a warning "comparing types of Unit and Int with != will always yield true". txt test file. getLines(). head, xs. StdIn package. write writes the supplied string to a new file: Scala 2 and 3. Jan 5, 2011 · val file: FileOps = Path ("file") // write bytes. Moving on from reading in the CSV file, we’ve Feb 18, 2013 · Scala is pretty good at making you never have to do more work than in Java, but especially with I/O, you often have to fall back to Java classes. val content: String = os. 2 GB and 33,444,922 lines. fromFile method. getProperty("config. import java. toList. I can convert the object ot string but it defeats the whole purpose of using the Yaml. Then filter the contents for punctuation and digits. id | name | subject 1 | a | science | | english When I do this Scala I get RDD[String] only. typesafe. Reading from files is really simple. Please convert file to UTF-8 encoding and then read. Writing a file all at once. fromBytes(text. To read a text file, create a object like this: val f = scala. I want to read lines from a text file and split and make changes to each lines and output them. txt") get the headers from the first row and zip them with index Dec 3, 2014 · I'm doing it this way right now: //println(line) lst = line. readLine("It will read it from here") May 26, 2015 · Or recombine entire files back to single strings (in this example the result is the same as what you get from wholeTextFiles, but with the string "file:" stripped from the filepathing. Value] Feb 20, 2011 · Here is a standard way to read Integer values. Dec 21, 2021 · Methods to read text files into an RDD. Each line in the file starts like so: Nov 24, 2021 · You could transform it to an array after reading it from the file by removing the brackets ([,]) using regexp_replace and splitting the remaining string by commas (,) using split eg. 3, “How to Split Strings in Scala”. close() I am pretty new to scala. java. – Shiwei Cao May 21, 2013 · 4. Here's what I have so far: Oct 25, 2015 · I need to edit question a bit, but the question still stands. This has the side effect of leaving the file open, but can be useful in short-lived programs, like shell scripts. Dec 18, 2014 · 1. May 1, 2017 · Alternatively, you can first copy the file to HDFS from the local file system and then launch Spark in its default mode (e. Just write the line inside readline and it will read it from there. lines. For example: How to read csv file into an Array of arrays in scala. I am running my job in yarn cluster mode. echo " 2019-07-02 22:11:11. get(filePath))). after { source. 3. csv("A. as[String]. ” Problem. grouped(2) . I am getting the data but it is in the form of an object. This solution shows both approaches. The given program is compiled and executed on the ubuntu 18. The lines to be removed can be identified with a substring match. 8 seconds. // the openOptions parameter takes a Mar 18, 2024 · res0: String = 42. id##name##subjects$$$ 1##a##science english$$$ 2##b##social mathematics$$$ I want to create a DataFrame like. However, based on the comments, it appears that you might actually be wanting to read data stored in a Google Sheet. At the time of this writing, there are no custom Scala libraries for reading YAML files, so Jun 21, 2013 · Now I want to read this CSV file and put the data into a Map[String,Array[String]] in Scala. txt” file which we created earlier. File. To fix it, you have the following options: Move the data file to HDFS. 0. Jun 4, 2016 · Once you've loaded the file contents like that, you can manipulate them as desired, such as searching the XML using XPath constructs like this: val temp = (xml \\ "channel" \\ "item" \ "condition" \ "@temp") text In summary, if you need to load an XML file in Scala, I hope this has been helpful. If you are reading a complex CSV file then the ideal solution is to use an existing library. Here's a snippit that reads a binary google . option("header", "false"). The Period It was the best of times, . Combine Recipe 12. aa: - x - y bb: z my code goes like this: Feb 4, 2019 · I am new to Scala. The Iterator. parallelize () to create the RDDs. That returns an Iterator, which is already lazy (You'd use stream as a lazy collection where you wanted previously retrieved values to be memoized, so you can read them again) If you're getting memory problems, then the problem will lie in what you're doing after getLines. txt") Like header option there are multiple options you can provide depending upon your requirement. txt is created and contains the string “Hello, This is Geeks For Geeks” Scala does not provide class to write a file but it provide a class to read the files. test("1 - foo file") {. yaml" with data. dir() / "output. fromFile(filename) val lines = (for (line <- bufferedSource. println(lst) It's giving me a redline on lst=line and says reassignment to a val. data file creation from Terminal or shell. Dec 7, 2021 · This is Recipe 12. Not sure why you want to get lines and then glue them all back together, though. You can use Scala’s Source class and its companion object to read files. I'm reading and writings some text files in Scala. It thought this would work: Mar 17, 2019 · A text file abc. Sep 29, 2014 · I want to read in a text file and filter lines that contain only certain values in a particular column. close } // assumes the file has the string "foo" as its first line. Summary: I’m working on a little project to parse relatively large (but not huge) Apache access log files, with the file this week weighing in at 9. findFirstIn(file. path") schema definition as simple string. Read file in Scala : Stream closed. Explore Teams Create a free Team Apr 17, 2018 · Is there any solution to read text from node using Scala. Maybe you can try: Aug 9, 2022 · As a quick note about reading files, if you ignore possible exceptions, you can use code like this read a text file into an Array, List, or Seq using Scala: val bufferedSource = io. continually approach lets you loop over each byte in the file. lines(path). Check this for more details. In this case, this will be a RDD[(String, String Aug 7, 2020 · 2. 11: scala. How can I use the relative path to read that file? (Do I have to move the movies. Each line in the json file is a json object (representing a tweet). Source; object Sample { // Main method def main ( args: Array[String]) { val file = Source. : Nov 13, 2010 · I tried a few things, favouring pattern matching as a way of avoiding casting but ran into trouble with type erasure on the collection types. Installation Dec 15, 2023 · In this section, we’ll cover how to read data from a YAML string and a YAML file with single and multiple documents. See full list on alvinalexander. I have a text file that has only one line with file words separated by a semi-colon(;). We can read file from console and check for the data and do certain operations over there. There are two main methods to read text files into an RDD: sparkContext. getBytes(), "UTF-8"). – mrog Commented May 1, 2015 at 18:32 . 000001, 01/01/2020, Aadi, xyz " > data. Given a simple CSV file like this named finance. Apr 10, 2019 · Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand Jun 16, 2015 · I'm trying to open a text file with Scala, read the first line, then the second, then the third. It looks like what you want to use is sc. scala> val fileRead = sc. gq ls fo sa cm yf hf to gq bx