Conventions

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The next lines of code read the link and assign it to the to the BeautifulSoup function."

A block of code is set as follows:

import org.apache.spark.sql.functions._      
 
val rdd = rawDS map GdeltParser.toCaseClass    
val ds = rdd.toDS()     
  
// DataFrame-style API 
ds.agg(avg("goldstein")).as("goldstein").show() 

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

spark.sql("SELECT V2GCAM FROM GKG LIMIT 5").show 
spark.sql("SELECT AVG(GOLDSTEIN) AS GOLDSTEIN FROM GKG WHERE GOLDSTEIN IS NOT NULL").show()

Any command-line input or output is written as follows:

$ cat 20150218230000.gkg.csv | gawk -F"\t" '{print $4}'

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "In order to download new modules, we will go to Files | Settings | Project Name | Project Interpreter."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.