Check if file exists in spark scala

 

For example, if you are processing logs, you may want to read files from a specific month. p = pathlib. is_dir() to see if it is a directory. format("csv") . csv" I am expecting output => csv Jun 6, 2014 · exists checks if at least one element(x) applies to function. 7. ls lists the content of a directory. It does not persist to memory unless you cache the dataset that underpins the view. findFirstIn(file. Jul 22, 2019 · I have a spark dataframe, and I wish to check whether each string in a particular column exists in a pre-defined a column of another dataframe. below code will work for hdfs,s3 & local filesystem. If any one of the does not exist, then i get 'u path does not exist' exception, And I dont want to get this exception. This should give you rdd data ( valid jsons) as. It should run in O(1) except when the RDD is empty, in which case it is linear in the number of partitions. code . You could try something like this, maybe looking to catch the specific exception that is being thrown when a file does not exist (I believe in Scala it's an AnalysisException): df = None. And it finally throws this "IOException: File already exists" after retries for the original failure. true – Returns if value presents in an array. scala> List[String]("apple", ""). Jul 30, 2009 · The function returns NULL if the index exceeds the length of the array and spark. SELECT * FROM (select * from objects) SPARK_GEN_SUBQ_11 WHERE 1=0 There is nothing wrong with using the if/else, but you could do this:. Dec 8, 2015 · RDD. sqlContext = SQLContext(spark. val columnNameToCheck Mar 17, 2019 · File Handling is a way to store the fetched information in a file. @Srinivas. length == 0. I checked the spark API and didnt find any method which checks if a file exists. If Table exist and I am running the second query in the first place then it throws Table already exists exception. exists() Jul 25, 2019 · If that succeeds I return True. Changed in version 3. Based on suggestions in this apache mail-thread and later some comments to this answer, I have done some small local experiments. File and java. hadoop. Something like this: paths = ["s3a://databricks-data/STAGING/" + str(ii Dec 10, 2018 · 0. head() will both return the java. Instead of enumerating each file and folder to find the desired Mar 10, 2016 · 14. Can use methods of Column, functions defined in pyspark. false – When a value not presents. eg. nio. You can use MSSparkUtils to work with file systems, to get environment variables, to chain notebooks together, and to work with secrets. r method. toSeq([hadoop_base_path]) Then there is a choice to be made: You can feed the index a NoopCache , which will save memory, but will scan the file-system for every query, including an Mar 5, 2018 · And in nutshell, it is usually not the real root cause that fails your job. tableExists("schemaname. New in version 3. map (file => io. filter(file => regex. io. I have shared my code below. enabled is set to false. Spark DataFrame has an attribute columns that returns all column names as an Array[String], once you have the columns, you can use the array function contains() to check if the column present. e ["A","Z"}, explode. import scala. 0 you can use one of the two approaches to check if a table exists. withColumn("word_check", dict. schema(schema) . In Spark use isin() function of Column class to check if a column value of DataFrame exists/contains in a list of string values. count() if exists > 0: print('3 exists in that column') – Mar 15, 2019 · Please provide me the spark code to check if a particular word exists in a file or not. format('csv'). Method Definition: def exists(p: (A) =&gt; Boolean): Boolean Return Type: It returns true if the predicate holds true for any of the elements of the stack or else returns false. implicits. 0: Supports Spark Connect. For writing to a file in scala we borrow java. import spark. (x: Column) -> Column: returning the Boolean expression. Unlike the basic Spark RDD API, the interfaces provided by Spark SQL provide Spark with more information about the structure of both the data and the computation being performed. is_file(): # or p. df. Jul 23, 2019 · How to check if path or file exist in Scala. Sep 14, 2020 · If a user clicks the "Create Folder" button in the Amazon S3 management console, a zero-length object is created with the same name as the folder. txt file to a location on HDFS. There is an option in Scala spark. Mar 19, 2021 · I am creating a function in Databricks to check if folder exists in Azure Blob Storage: import java. 11) for Livy to work with this setup May 27, 2021 · In Databricks' Scala language, the command dbutils. WrappedArray to describe the Set - not sure which is correct but neither work): Jun 4, 2020 · Stack Overflow Public questions & answers; Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Talent Build your employer brand Dec 15, 2021 · I want ignore the paths that generate the Error: 'Path does not exist'. val data = Seq(. We could also import java. Check if values of column pyspark df exist in other column pyspark df. You could do this before saving the file: Dec 13, 2018 · If you don't want to use UDF, then you can introduce a new column for the check list i. contains(keyword)). fromFile(file)) } Note that this won't fetch files in sub-directories, doesn't have more advance globbing Feb 6, 2020 · I am working in scala and spark environment where I want to read parquet file. filter(col('col2') == 3). txt") val count= rdd. contains("name") df. It would also be better to use the Hadoop configuration of your current Spark context, to ensure you will use the same file system settings as Spark. first() calls head() directly, which calls head(1). tablename"). Nov 6, 2017 · You first need to obtain the right file system by providing an URI from a path which contains the s3 scheme and your bucket. For example I have a list of paths: list_paths = ['path1','path2','path3'] and read the files like: dataframe = spark. For file copy or move operations, you can check a faster option of running filesystem operations described in Parallelize filesystem operations. You can use listTopics() or describeTopics(). Variables only exist at compile time so you can't dynamically create or delete variables at runtime. ansi. URI import org Method and Description. then check if the skills contains the exploded items, filter and then drop duplicates on the skills column. scala> val s = Seq(1,2,3). I have a two step process in which the first step write a SUCCESS. Apr 24, 2024 · Home » Apache Spark » Spark Filter Using contains () Examples. Oct 30, 2018 · @HaukeMallow Thanks for replying, I have shared my code below, I am facing issues, I call a function sqlContext. Mar 16, 2018 · The exists function is applicable to both Scala's Mutable and Immutable collection data structures. Stack Overflow. Spark: Check whether a value exists in a nested array without exploding. Scala 2. Answer could be improved further by noting Python syntax which is often but not always very similar to the Scala equivalent. fs. Jan 10, 2022 · I want to check whether a file exists in an s3 path and then read it as a spark dataframe. csv is null or not. spark. But what about views? If it create it like this: df = sqlContext. Creating SQL Context from Spark Session's Context. ls(dir) except: return False return True Feb 14, 2023 · Luckily, Spark provides a utility for converting a Python list into a Scala Seq: hadoop_base_path = jvm. def fileExists (arg1): try: dbutils. Main problem - you can't distinguish between files/directories that doesn't exist and files/directories to which you don't have access permissions: def file_exists(dir): try: dbutils. So, coming from a Python background, I figured I could create a list of folders from a sequence and then test whether such a folder exists, and if so, read the data, if not, skip. NoSuchElementException if the DataFrame is empty. table_name""") if the table doesn't exist then the first query gives exception of Table Does not exist. Using this new module, you can check whether a file exists like this: import pathlib. May 17, 2019 · Check if a file exists in azure blob container 2 Databricks / pyspark: How to get all full directory paths (that have at least one file as content) from Azure Blob storage recursively Apr 29, 2021 · 2. createDataFrame(testList) // define the hasColumn function. with Python equivalent: Using df. contains(d))) But i get the error: type mismatch; found : org. load(<string with comma seperated paths>). functions and Scala UserDefinedFunctions. csv*") If you have multiple paths in inputPaths for instance, you can filter them as. So what I am trying is: Nov 5, 2019 · I need to check if a temp file exists or not using scala, how can i do this. Full code here. getAs[String]("downloadUrl") val title = row. This method returns a boolean indicating if the file or directory denoted by the given pathname exists: scala> import java. Asking for help, clarification, or responding to other answers. find(x=>x == myString) match {. Path('path/to/file') if p. sql("""DROP TABLE IF EXISTS db_name. Say the job executed and created a partition for date 20210906. option() returns a DataFrameReader. overwrite("<p>Just one paragraph</p>") How to read a file. parquet(*list_paths) but the path path2 does not exist. Define the path to the file. Regex) = {. However , same functionality not available through pySpark. 0, my suggestion would be to use head(n: Int) or take(n: Int) with isEmpty, whichever one has the clearest intent to you. addFile() when the target file exists and its contents do not match those of the source. To create new bucket, use create_bucket method. ) try using Apache Hadoop utils: Dec 18, 2014 · A bit rough on the edges, but maybe something like : def getFilesMatchingRegex(dir: String, regex: util. Column` Examples Apr 15, 2019 · I am writing a scala UDF which takes values from a column and check if specific values in a list exists then do something and if some other value exists do something and so on. FileSystem scala> import org. Regex val numberPattern: Regex = "[0-9]". Sep 6, 2017 · I was assuming that Google Storage connector would allow to query GS directly as if it was HDFS from Spark in Dataproc, but it looks like the following does not work (from Spark Shell): scala> import org. 0, it is an entry point to underlying Spark functionality in order to programmatically create Spark RDD, DataFrame, and DataSet. Looking for a quick and clean approach to check if Hive table exists using PySpark Spark SQL is a Spark module for structured data processing. toDF("num") May 20, 2017 · package scala object sys { /** A bidirectional, mutable Map representing the current system Properties. For example: val I need to check if a string is present in a list, and call a function which accepts a boolean accordingly. Oct 11, 2018 · I understand how to check for table existence in PySpark: >>> spark. Function0<String> errorMsg) long offset, long length, org. conf. Jul 7, 2022 · 3. from pyspark. Scala 3. Source. SystemProperties]] */ def props: SystemProperties = new SystemProperties /** An immutable Map representing the current system environment. so, in that case, I need to Jul 25, 2019 · If that succeeds I return True. matching. listFiles. SparkSession’s object spark is the default variable available in spark-shell and it can be created programmatically using SparkSession builder def check_for_files(path_to_files: str, text_to_find: str) -> bool: """ Checks a path for any files containing a string of text """ files_found = False Aug 1, 2022 · Try to list a path, and catch exception when file doesn't exist or not accessible. April 24, 2024. parquet(s"blablah") May 20, 2018 · Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. If yes, also put them in array_intrval. sparkContext) I want to check if a table schemaname. I can call the method twice that's not a concern. class WriteReport(val run: String = "run1") {. read. Configuration conf) Get the locations of the HDFS blocks containing the given file segment. util. Input come in different file formats such as CVS, excel and orc etc. columns returns only top level columns but not nested struct columns. The file couldn't exists so for that reason I have to check if exists. Databricks spark-csv check for empty file. For file system list and delete operations, you can refer to parallel listing and delete methods utilizing Spark in How to list and delete files faster in Databricks . Put that in a function, call the function with your filename and you are good to go. Provide details and share your research! But avoid …. Mar 1, 2021 · There are occasionally some of these folders missing, and it's not systematic or predictable. However, it must be only deleted after run2, and not run1. So find and solve the real root cause, it will also gone. Please note, that in order to read/write to the bucket, there is a need to set proper permissions for the storage. contains(). txt file exists before it starts processing the data. // do something. If you want to check if a Column exists with the same Data Type, then use the Spark schema functions df. |-- Location: struct (nullable = true) | |-- filter: struct (nullable = true) | | |-- Disaster: string (nullable = true) Nov 25, 2016 · 1. To test if a file or directory exists, we can use the File#exists () method. Importing required libraries. Jul 13, 2017 · After this, I want to check whether a exists in array_intrval, if not add a in array_intrval and then check whether there are some elements which is less than or equal to a. for path in paths_to_read: try: temp_df = sqlContext \. scala> :paste // Entering paste mode (ctrl-D to finish) import org. Parquet is a file format rather than a database, in order to achieve an update by id, you will need to read the file, update the value in memory, than re-write the data to a new file (or overwrite the existing file). net. case class Test(a: Int, b: Int) val testList = List(Test(1,2), Test(3,4)) val testDF = sqlContext. Internally, Spark SQL uses this extra information to perform extra optimizations. If spark. apache spark - check if file exists. files. io Oct 28, 2015 · PS: I also checked this thread: Spark iterate HDFS directory but it does not work for me as it does not seem to search on hdfs directory, instead only on the local file system with schema file//. Check if value from one dataframe column exists in another dataframe column using Spark Scala 3 Spark (scala) dataframes - Check whether strings in column exist in a column of another dataframe Oct 8, 2020 · According to the DeltaTable's Javadoc, you can check that there is a delta table in specified path with the following command: DeltaTable. PythonUtils. enabled is set to true, it throws ArrayIndexOutOfBoundsException for invalid indices. scala> File("/tmp/baeldung. Before I read, I want to check if the file exists or not. isDefined) . // define test data. Path import org. Hadoop Mapreduce word count Can use methods of Column, functions defined in pyspark. Note that df. File(dir). isDeltaTable(spark, "path/to/table") If the path does not contain delta table or doesn't exist, it will return false. schema. AND NOT can be rewritten using EXCEPT. Path(base_path) paths = jvm. In order to explain how it works, first let’s create a DataFrame. exists(d => $"words". Aug 26, 2020 · or you if you want to check that csv exist, you can first check existence of file. Updated code to work for hdfs & s3. tablename exists in Hive using pysparkSQL. Column required: Boolean I have also tried to create a UDF to do this (using both mutable. test_table") df. I also needed to copy over apache-hive jars (scala 2. {StringType, StructField} df. functions. If you want your code to be applicable for all filesystems (local, in Docker (CI/CD), S3, HDFS, etc. This 'forces' the folder to appear even if there are no objects 'inside' the folder. In the context of the previous example we can see how to write entirely new content to a file: html. 2) Assuming you don't have any privilege access to the cluster (to check metrics or liveness probes), the only way to check the cluster is running is to try connecting to/use it. FileSystem Jan 25, 2024 · Microsoft Spark Utilities (MSSparkUtils) is a builtin package to help you easily perform common tasks. Sep 25, 2018 · spark. Yes, you can use a library like this, to check if a file exists in S3. , for example input =>"D:\\resources\\core_dataset. Apr 9, 2024 · array_contains() works like below. NET Spark (C#), and R (Preview) notebooks and Aug 19, 2021 · var keyword="my_keyword" val rdd=sparkContext. . 0) with spark 2. Options: The -e option will check to see if the file exists, returning 0 if true. Let’s see with an example. Aug 25, 2019 · In pyspark 2. To access Google Cloud storage bucket, use Google Cloud Client libraries: To check if bucket exist, use get_bucket method and it is also possible to access bucket metadata. 3. setCurrentDatabase("staging") >>> 'test_table' in sqlContext. length==0. " OR can always be rewritten using UNION. getAs[String]("title") // here I want to see if the downloadUrl is null. s. If I need to rerun the job on the same date (ad hoc runs are a project requirement), it will just append the data output by the 2nd run into the partition created by the first run. Please read with your own judgement! org. SparkSession was introduced in version Spark 2. File def checkFolder(paths: List[String]): Unit = { for (f &lt;- paths) { try Things on this page are fragmentary and immature notes/thoughts of the author. scala Oct 27, 2021 · I am searching for a one line solution to check if a string contain any item from a List. Use a glob pattern match to select specific files in a folder. table_name""") spark. 4. However, I'm working on a notebook in Azure Synapse and it doesn't have dbutils package. createOrReplaceTempView("test_view") Oct 29, 2020 · Any hadoop free version of spark should work, for me though, this is what worked: Hadoop 3. Sep 3, 2021 · as far as I can see, the answer here is incorrect. 38. Aug 21, 2019 · I wouldn't use java. Actually you don't even need to call select in order to use columns, you can just call it on the dataframe itself. 0. file, it doesn't have a proper binding to S3 and/or HDFS. Now you can read the json rdd into dataframe. Another way would be to use the Filesystem. load does will not load all the objects into a dataframe. parquet(path) if df is None: Mar 22, 2021 · I am trying to read a file from HDFS but I am having a problem here. Mar 27, 2024 · Solution: Using isin () & NOT isin () Operator. So both x and y must be defined at compile time or else the compiler will reject the code. with schema as. isEmpty) res30: Boolean = false Same happens with Option. Get method like this: var sc = new SparkContext() Mar 27, 2024 · 4. split(","). exists () function in Python: Import the os module. You might be better served using a database if this is a use-case that will occur frequently. I am a beginner in Scala and not able perform Jul 15, 2019 · Spark [Scala]: Checking if all the Rows of a smaller DataFrame exists in the bigger DataFrame 3 Spark (scala) dataframes - Check whether strings in column exist in a column of another dataframe Oct 23, 2014 · Hadoop fs is deprecated Usage: hdfs dfs -test -[ezd] URI. prop. strings. :return: a :class:`~pyspark. exists. types. load(inputPath + "/*. val downloadUrl = row. val df: DataFrame = spark. Path Jul 17, 2020 · Check below code. val report = spark. fieldNames. Examples: > SELECT elt (1, 'scala', 'java'); scala > SELECT elt (2, 'a', 1); 1. option("delimiter", ",") . Please check below code. The most robust way to read all lines of text from a file is: Check whether nested data exist on parquet scala spark or not? 0. 9. As per the Scala documentation, the definition of the exists method is as follows: def exists ( p: ( A) ⇒ Sep 15, 2017 · There is a workaround for this by using wholeTextFiles api. Regex import java. 1 answer. case Some(_) => myFunction(true) The answer is very nicely detailed, buy OP's tags & question are clearly Python-focused and this answer is done entirely in Scala. exists = df. Spark Check if Column Exists in DataFrame. In Databricks, check whether a Nov 17, 2021 · 0. first() and df. r numberPattern. Therefore, it is not possible to "check if the listed path is a file or a Aug 1, 2017 · df. {FileSystem, Path, RemoteIterator} import org. May 6, 2023 · Since Scala can use any java library, the first possibility is using the Java standard IO module. Nov 20, 2014 · The documentation for the parameter spark. 2. What you can do is use Option to indicate whether a variable has a value or not: def checkVar(v: Option[Int]) = v. Once it's removed, the class runs twice, and append the results to the parquet file. spark-sql; scala; hadoop +1 vote. find(_. findFirstMatchIn("awesomepassword") match { case Some(_) => println Apr 27, 2021 · If any problem is found, that means your directory does not exists, it may be because of the lowercase c: , try with it in uppercase and check if dir exists In order to be sure, i'll consider checking if the directory exists as follows: Mar 27, 2024 · What is SparkSession. You would have to upload the jar to S3 so you can reference it in your Glue Job as an external library. isEmpty() will be part of Spark 1. Check if value presents in an array ( ArrayType) column. Mar 27, 2019 · apache spark - check if file exists. May 23, 2022 · Select files using a pattern match. MSSparkUtils are available in PySpark (Python), Scala, . 0. 1. Returns whether a predicate holds for one or more elements in the array. Apr 27, 2018 · I want to check if . Configuration conf) Check if the file exists at the given path. when you call load on it , it will test the connection and issue a query like. spark. Another useful input operation is an overwriting. The os. The -z option will check to see if the file is zero length, returning 0 if true. txt"). spark test on local machine. empty, as theres no element in it, Jan 7, 2020 · LEFT SEMI JOIN is equivalent to the EXISTS function in Spark. org. which should give you. table_name = 'table_name'. db_name = None. path. Jun 22, 2023 · 1. # do stuff. Feb 3, 2022 · Lastly if you want to push reach row to an external API, use a foreach each instead. flatMap(c => list. overwrite says this: "Whether to overwrite files added through SparkContext. new java. sys. * * @return a SystemProperties. exists () function returns a boolean value: True if the file exists, False if it does not exist. foreach(row=>{. exists () function to check if the file exists. sql. functions and Scala UserDefinedFunctions . tableNames() True. _ from Java because we don’t have a class to write into a file, in the Scala standard library. About; Products For Teams; apache spark - check if file exists. take(1). Check if a Field Exists in a DataFrame. Regular expressions are strings which can be used to find patterns (or lack thereof) in data. " So it has no effect on saveAsTextFiles method. filter(line=>line. apache. May 22, 2015 · I am new to spark and I have a question. So your code would be: val del_ID = "Check_ID ="+ "123". _. File. When selecting files, a common requirement is to only read specific files from a folder. Set and mutable. scala. schema Jun 2, 2020 · Boolean true or false, based on if file exists in source or target. Below example filter the rows language column value present in ‘ Java ‘ & ‘ Scala ‘. textFile("test_file. If not null and contains record then process the file otherwise exit. May 13, 2019 · I am trying to find the file type in order to read the file based on its type. Is it possible to achieve this with a one liner? The code below is the best I could get: val strings = List("a", "b", "c") val myString = "a". The spark task may be failed by other reason. Apache Spark / Member. org. // Check if a Field Exists in a DataFrame import org. when I read parquet files with pyspark. rdd. FileSystem import org. Keep in mind that the Spark Session ( spark) is already created. Then use the predicate to determine whether the row should be pushed. You are calculating the sum values via aggregation. null – when the array is null. ## Function to check to see if a file exists. 2. . sql import SQLContext. catalog. map(_ => Result("Found May 17, 2017 · createOrReplaceTempView creates (or replaces if that view name already exists) a lazily evaluated "view" that you can then use like a hive table in Spark SQL. Example: String: "This is A and B and C" Expected Output: If List =["A", "B] then true Oct 4, 2016 · Also you can write directly bytes in a file. However, it is not actually a folder. If a does exists in array_intrval, skip a and check for next element in joint_matrix. Naveen Nelamali. option(). "Although Apache Spark SQL currently does not support IN or EXISTS subqueries, you can efficiently implement the semantics by rewriting queries to use LEFT SEMI JOIN. getName). head. Python UserDefinedFunctions are not supported (SPARK-27052). Mar 26, 2024 · In Scala Stack class, the exists() method is utilized to check whether a predicate holds for any of the elements of the stack. fieldNames or df. I am writing the following code in jupyter notebook but it does not work - meaning it does not show any frame because the function testDirExist returns false May 30, 2024 · Follow these steps to check if a file exists using the os. sql("""Create TABLE IF NOT EXISTS db_name. The best method is using take(1). isEmpty) res21: Boolean = true //if theres no element then obviously returns false scala> List[String](). If you want to check if a column contains a value, you could filter the dataframe on that column and see if there are any rows left. sql("SELECT * FROM staging. exists(_. Use the os. Return one of the below values. head (arg1,1) except: return False; else: return True; Calling that function with your filename. If the file exists I read that file, otherwise I read an empty DF. Spark-scala : Check whether a S3 directory exists or not before reading it. pyspark. contains(c))) . The problem is I do not know the exact path of the file, so I have to use wild characters. Is there a way to check in Spark Scala code if file is empty or not? Mar 26, 2019 · 1. Sep 1, 2020 · I'm trying check if the output file exists, if it does, then remove it. The exists method takes a predicate function and will use it to find the first element in the collection which matches the predicate. I have found a same problem in Spark (scala) dataframes - Check whether strings in column contain any items from a set Apr 20, 2023 · You can call this method as follows to list all WAV and MP3 files in a given directory: val okFileExtensions = List("wav", "mp3") val files = getListOfFiles(new File("/tmp"), okFileExtensions) As long as this method is given a directory that exists, this method will return an empty List if no matching files are found: scala> val files Sep 22, 2015 · For Spark 2. * @see [[scala. 3. nonEmpty. ¶. Any string can be converted to a regular expression using the . Scala provides packages from which we can create, open, read and write the files. 1 (wildfly issues with 3. read \. 1. count print(“Found” if count>0 else “Not Found”) Main difference is first one using map and then reducing whereas second one is filtering and doing a count. You can (and usually should) still use a try/except block when opening files: try: Language. EXISTS & IN can always be rewritten using JOIN or LEFT SEMI JOIN. 1) The recommended way to check if a topic exists is to use the AdminClient API. Sep 6, 2021 · the idea is to delete the existing partition in case of a rerun. My second step which is a spark job has to verify if that SUCCESS. bm ku wa wm nn wa vg gy no bh