Get started: Import and visualize CSV data from a notebook

This article walks you through using an Azure Databricks notebook to import data from a CSV file containing baby name data from health.data.ny.gov into your Unity Catalog volume using Python, Scala, and R. You also learn to modify a column name, visualize the data, and save to a table.

Requirements

To complete the tasks in this article, you must meet the following requirements:

• Your workspace must have Unity Catalog enabled. For information on getting started with Unity Catalog, see Set up and manage Unity Catalog.
• You must have the WRITE VOLUME privilege on a volume, the USE SCHEMA privilege on the parent schema, and the USE CATALOG privilege on the parent catalog.
• You must have permission to use an existing compute resource or create a new compute resource. See Get started with Azure Databricks or see your Databricks administrator.

Step 1: Create a new notebook

To create a notebook in your workspace, click New in the sidebar, and then click Notebook. A blank notebook opens in the workspace.

To learn more about creating and managing notebooks, see Manage notebooks.

Step 2: Define variables

In this step, you define variables for use in the example notebook you create in this article.

1. Copy and paste the following code into the new empty notebook cell. Replace <catalog-name>, <schema-name>, and <volume-name> with the catalog, schema, and volume names for a Unity Catalog volume. Optionally replace the table_name value with a table name of your choice. You will save the baby name data into this table later in this article.

2. Press Shift+Enter to run the cell and create a new blank cell.

   Python

   catalog = "<catalog_name>"
   schema = "<schema_name>"
   volume = "<volume_name>"
   download_url = "https://health.data.ny.gov/api/views/jxy9-yhdk/rows.csv"
   file_name = "baby_names.csv"
   table_name = "baby_names"
   path_volume = "/Volumes/" + catalog + "/" + schema + "/" + volume
   path_table = catalog + "." + schema
   print(path_table) # Show the complete path
   print(path_volume) # Show the complete path
   

   Scala

   val catalog = "<catalog_name>"
   val schema = "<schema_name>"
   val volume = "<volume_name>"
   val downloadUrl = "https://health.data.ny.gov/api/views/jxy9-yhdk/rows.csv"
   val fileName = "baby_names.csv"
   val tableName = "baby_names"
   val pathVolume = s"/Volumes/${catalog}/${schema}/${volume}"
   val pathTable = s"${catalog}.${schema}"
   print(pathVolume) // Show the complete path
   print(pathTable) // Show the complete path
   

   R

   catalog <- "<catalog_name>"
   schema <- "<schema_name>"
   volume <- "<volume_name>"
   download_url <- "https://health.data.ny.gov/api/views/jxy9-yhdk/rows.csv"
   file_name <- "baby_names.csv"
   table_name <- "baby_names"
   path_volume <- paste("/Volumes/", catalog, "/", schema, "/", volume, sep = "")
   path_table <- paste(catalog, ".", schema, sep = "")
   print(path_volume) # Show the complete path
   print(path_table) # Show the complete path
   

Step 3: Import CSV file

In this step, you import a CSV file containing baby name data from health.data.ny.gov into your Unity Catalog volume.

1. Copy and paste the following code into the new empty notebook cell. This code copies the rows.csv file from health.data.ny.gov into your Unity Catalog volume using the Databricks dbutuils command.

2. Press Shift+Enter to run the cell and then move to the next cell.

   Python

   dbutils.fs.cp(f"{download_url}", f"{path_volume}" + "/" + f"{file_name}")
   

   Scala

   dbutils.fs.cp(downloadUrl, s"${pathVolume}/${fileName}")
   

   R

   dbutils.fs.cp(download_url, paste(path_volume, "/", file_name, sep = ""))
   

Step 4: Load CSV data into a DataFrame

In this step, you create a DataFrame named df from the CSV file that you previously loaded into your Unity Catalog volume by using the spark.read.csv method.

1. Copy and paste the following code into the new empty notebook cell. This code loads baby name data into DataFrame df from the CSV file.

2. Press Shift+Enter to run the cell and then move to the next cell.

   Python

   df = spark.read.csv(f"{path_volume}/{file_name}",
     header=True,
     inferSchema=True,
     sep=",")
   

   Scala

   val df = spark.read
       .option("header", "true")
       .option("inferSchema", "true")
       .option("delimiter", ",")
       .csv(s"${pathVolume}/${fileName}")
   

   R

   # Load the SparkR package that is already preinstalled on the cluster.
   library(SparkR)
   
   df <- read.df(paste(path_volume, "/", file_name, sep=""),
     source="csv",
     header = TRUE,
     inferSchema = TRUE,
     delimiter = ",")
   

You can load data from many supported file formats.

Step 5: Visualize data from notebook

In this step, you use the display() method to display the contents of the DataFrame in a table in the notebook, and then visualize the data in a word cloud chart in the notebook.

1. Copy and paste the following code into the new empty notebook cell, and then click Run cell to display the data in a table.

   Python

   display(df)
   

   Scala

   display(df)
   

   R

   display(df)
   

2. Review the results in the table.

3. Next to the Table tab, click + and then click Visualization.

4. In the visualization editor, click Visualization Type, and verify that Word cloud is selected.

5. In the Words column, verify that First Name is selected.

6. In Frequencies limit, click 35.

   

7. Click Save.

Step 6: Save the DataFrame to a table

1. Copy and paste the following code into an empty notebook cell. This code replaces a space in the column name. Special characters, such as spaces are not allowed in column names. This code uses the Apache Spark withColumnRenamed() method.

   Python

   df = df.withColumnRenamed("First Name", "First_Name")
   df.printSchema
   

   Scala

   val dfRenamedColumn = df.withColumnRenamed("First Name", "First_Name")
   // when modifying a DataFrame in Scala, you must assign it to a new variable
   dfRenamedColumn.printSchema()
   

   R

   df <- withColumnRenamed(df, "First Name", "First_Name")
   printSchema(df)
   

2. Copy and paste the following code into an empty notebook cell. This code saves the contents of the DataFrame to a table in Unity Catalog using the table name variable that you defined at the start of this article.

   Python

   df.write.mode("overwrite").saveAsTable(f"{path_table}" + "." + f"{table_name}")
   

   Scala

   dfRenamedColumn.write.mode("overwrite").saveAsTable(s"${pathTable}.${tableName}")
   

   R

   saveAsTable(df, paste(path_table, ".", table_name), mode = "overwrite")
   

3. To verify that the table was saved, click Catalog in the left sidebar to open the Catalog Explorer UI. Open your catalog and then your schema to verify that the table appears.

4. Click your table to view the table schema on the Overview tab.

5. Click Sample Data to view 100 rows of data from the table.

Import and visualize data notebooks

Use one of the following notebooks to perform the steps in this article. Replace <catalog-name>, <schema-name>, and <volume-name> with the catalog, schema, and volume names for a Unity Catalog volume. Optionally replace the table_name value with a table name of your choice.

Python

Import data from CSV using Python

Get notebook

Scala

Import data from CSV using Scala

Get notebook

R

Import data from CSV using R

Get notebook

Next steps

• To learn about adding additional data into existing table from a CSV file, see Get started: Ingest and insert additional data.
• To learn about cleansing and enhancing data, see Get started: Enhance and cleanse data.

Additional resources

• Get started: Query and visualize data from a notebook
• Tutorial: Load and transform data using Apache Spark DataFrames