yq/pkg/yqlib/doc/usage/csv-tsv.md

CSV

Encode/Decode/Roundtrip CSV and TSV files.

Encode

Currently supports arrays of homogeneous flat objects, that is: no nesting and it assumes the first object has all the keys required:

- name: Bobo
  type: dog
- name: Fifi
  type: cat

As well as arrays of arrays of scalars (strings/numbers/booleans):

- [Bobo, dog]
- [Fifi, cat]

Decode

Decode assumes the first CSV/TSV row is the header row, and all rows beneath are the entries. The data will be coded into an array of objects, using the header rows as keys.

name,type
Bobo,dog
Fifi,cat

Encode CSV simple

Given a sample.yml file of:

- [i, like, csv]
- [because, excel, is, cool]

then

yq -o=csv sample.yml

will output

i,like,csv
because,excel,is,cool

Encode TSV simple

Given a sample.yml file of:

- [i, like, csv]
- [because, excel, is, cool]

then

yq -o=tsv sample.yml

will output

i	like	csv
because	excel	is	cool

Encode array of objects to csv

Given a sample.yml file of:

- name: Gary
  numberOfCats: 1
  likesApples: true
  height: 168.8
- name: Samantha's Rabbit
  numberOfCats: 2
  likesApples: false
  height: -188.8

then

yq -o=csv sample.yml

will output

name,numberOfCats,likesApples,height
Gary,1,true,168.8
Samantha's Rabbit,2,false,-188.8

Encode array of objects to custom csv format

Add the header row manually, then the we convert each object into an array of values - resulting in an array of arrays. Pick the columns and call the header whatever you like.

Given a sample.yml file of:

- name: Gary
  numberOfCats: 1
  likesApples: true
  height: 168.8
- name: Samantha's Rabbit
  numberOfCats: 2
  likesApples: false
  height: -188.8

then

yq -o=csv '[["Name", "Number of Cats"]] +  [.[] | [.name, .numberOfCats ]]' sample.yml

will output

Name,Number of Cats
Gary,1
Samantha's Rabbit,2

Encode array of objects to csv - missing fields behaviour

First entry is used to determine the headers, and it is missing 'likesApples', so it is not included in the csv. Second entry does not have 'numberOfCats' so that is blank

Given a sample.yml file of:

- name: Gary
  numberOfCats: 1
  height: 168.8
- name: Samantha's Rabbit
  height: -188.8
  likesApples: false

then

yq -o=csv sample.yml

will output

name,numberOfCats,height
Gary,1,168.8
Samantha's Rabbit,,-188.8

Parse CSV into an array of objects

First row is assumed to be the header row.

Given a sample.csv file of:

name,numberOfCats,likesApples,height
Gary,1,true,168.8
Samantha's Rabbit,2,false,-188.8

then

yq -p=csv sample.csv

will output

- name: Gary
  numberOfCats: 1
  likesApples: true
  height: 168.8
- name: Samantha's Rabbit
  numberOfCats: 2
  likesApples: false
  height: -188.8

Parse TSV into an array of objects

First row is assumed to be the header row.

Given a sample.tsv file of:

name	numberOfCats	likesApples	height
Gary	1	true	168.8
Samantha's Rabbit	2	false	-188.8

then

yq -p=tsv sample.tsv

will output

- name: Gary
  numberOfCats: 1
  likesApples: true
  height: 168.8
- name: Samantha's Rabbit
  numberOfCats: 2
  likesApples: false
  height: -188.8

Round trip

Given a sample.csv file of:

name,numberOfCats,likesApples,height
Gary,1,true,168.8
Samantha's Rabbit,2,false,-188.8

then

yq -p=csv -o=csv '(.[] | select(.name == "Gary") | .numberOfCats) = 3' sample.csv

will output

name,numberOfCats,likesApples,height
Gary,3,true,168.8
Samantha's Rabbit,2,false,-188.8