Working with CSVs

Learning objectives

• use AWK on a CSV

For teachers

Teaching goals are:

• Learners can use AWK on a CSV

Lesson plan:

• 5 mins: prior knowledge
• 5 mins: presentation
• 15 mins: challenge
• 5 mins: feedback

Overview

In this session, we use AWK on a file with comma-separated values.

Exercises

See the exercise procedure here.

Exercise 1: confirming things are true

Learning objectives

• experience the ways to filter on column values of awk

Download the data

In a terminal, do:

wget https://raw.githubusercontent.com/richelbilderbeek/awk_course/master/data/diamonds_raw.csv

to download a file called diamonds_raw.csv.

mix between string and values

In a terminal, in the same folder as where the data is downloaded, do:

awk 'NR < 10 { print $1 }' diamonds_raw.csv

In English, this is: 'For every line with a line number less than 10, print the first column's value'.

Confirm that this is true if the columns are separated by a tab.

mix between string and values

In a terminal, in the same folder as where the data is downloaded, do:

awk -F "," 'NR < 10 { print $1 }' diamonds_raw.csv

In English, this is: 'Columns are separated by a comma. For every line with a line number less than 10, print the first column's value'.

Confirm that this is true.

multi-word strings

In a terminal, in the same folder as where the data is downloaded, do:

awk -F "," 'NR < 10 { print $2 }' diamonds_raw.csv

In English, this is: 'Columns are separated by a comma. For every line with a line number less than 10, print the seconds column's value'.

Confirm that this is true.