There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "The file we are using in this project (combine.csv) is a comma-delimited text file containing statistics on players who attended the NFL scouting combine."

A block of code is set as follows:

df_data_2.createOrReplaceTempView("station")
sqlDF = spark.sql("SELECT * FROM station where VALUE > 200")
sqlDF.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:

[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)
exten => s,102,Voicemail(b100)
exten => i,1,Voicemail(s0)

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "If you click on the blue Cloud sign-up/log-in link, you can create a free account (using your IBM ID) or log in (once you have set up your paid or free account)."