String Operators
Case insensitive tip: prefix the regex with
(?i)
- e.g. test("(?i)cats)"
.This operator returns the substring match details of the given regEx.
Capture returns named RegEx capture groups in a map. Can be more convenient than
match
depending on what you are doing.Returns true if the string matches the RegEx, false otherwise.
Substitutes matched substrings. The first parameter is the regEx to match substrings within the original string. The second parameter specifies what to replace those matches with. This can refer to capture groups from the first RegEx.
Bash is notorious for chomping on precious trailing newline characters, making it tricky to set strings with newlines properly. In particular, the
$( exp )
will trim trailing newlines.For instance to get this yaml:
a: |
cat
Using
$( exp )
wont work, as it will trim the trailing newline.m=$(echo "cat\n") yq -n '.a = strenv(m)'
a: cat
However, using printf works:
printf -v m "cat\n" ; m="$m" yq -n '.a = strenv(m)'
a: |
cat
As well as having multiline expressions:
m="cat
" yq -n '.a = strenv(m)'
a: |
cat
Similarly, if you're trying to set the content from a file, and want a trailing newline:
IFS= read -rd '' output < <(cat my_file)
output=$output ./yq '.data.values = strenv(output)' first.yml
Works with unicode characters
Given a sample.yml file of:
água
then
yq 'upcase' sample.yml
will output
ÁGUA
Works with unicode characters
Given a sample.yml file of:
ÁgUA
then
yq 'downcase' sample.yml
will output
água
Given a sample.yml file of:
- cat
- meow
- 1
- null
- true
then
yq 'join("; ")' sample.yml
will output
cat; meow; 1; ; true
Given a sample.yml file of:
- ' cat'
- 'dog '
- ' cow cow '
- horse
then
yq '.[] | trim' sample.yml
will output
cat
dog
cow cow
horse
Given a sample.yml file of:
foo bar foo
then
yq 'match("foo")' sample.yml
will output
string: foo
offset: 0
length: 3
captures: []
Given a sample.yml file of:
foo bar FOO
then
yq '[match("(?i)foo"; "g")]' sample.yml
will output
- string: foo
offset: 0
length: 3
captures: []
- string: FOO
offset: 8
length: 3
captures: []
Given a sample.yml file of:
abc abc
then
yq '[match("(ab)(c)"; "g")]' sample.yml
will output
- string: abc
offset: 0
length: 3
captures:
- string: ab
offset: 0
length: 2
- string: c
offset: 2
length: 1
- string: abc
offset: 4
length: 3
captures:
- string: ab
offset: 4
length: 2
- string: c
offset: 6
length: 1
Given a sample.yml file of:
foo bar foo foo foo
then
yq '[match("foo (?P<bar123>bar)? foo"; "g")]' sample.yml
will output
- string: foo bar foo
offset: 0
length: 11
captures:
- string: bar
offset: 4
length: 3
name: bar123
- string: foo foo
offset: 12
length: 8
captures:
- string: null
offset: -1
length: 0
name: bar123
Given a sample.yml file of:
xyzzy-14
then
yq 'capture("(?P<a>[a-z]+)-(?P<n>[0-9]+)")' sample.yml
will output
a: xyzzy
n: "14"
Given a sample.yml file of:
cat cat
then
yq 'match("cat")' sample.yml
will output
string: cat
offset: 0
length: 3
captures: []
Given a sample.yml file of:
cat cat
then
yq '[match("cat"; "g")]' sample.yml
will output
- string: cat
offset: 0
length: 3
captures: []
- string: cat
offset: 4
length: 3
captures: []
Like jq's equivalent, this works like match but only returns true/false instead of full match details
Given a sample.yml file of:
- cat
- dog
then
yq '.[] | test("at")' sample.yml
will output
true
false
This uses Golang's regex, described here. Note the use of
|=
to run in context of the current string value.Given a sample.yml file of:
a: dogs are great
then
yq '.a |= sub("dogs", "cats")' sample.yml
will output
a: cats are great
This uses Golang's regex, described here. Note the use of
|=
to run in context of the current string value.Given a sample.yml file of:
a: cat
b: heat
then
yq '.[] |= sub("(a)", "${1}r")' sample.yml
will output
a: cart
b: heart
When custom tags are encountered, yq will try to decode the underlying type.
Given a sample.yml file of:
a: !horse cat
b: !goat heat
then
yq '.[] |= sub("(a)", "${1}r")' sample.yml
will output
a: !horse cart
b: !goat heart
Given a sample.yml file of:
cat; meow; 1; ; true
then
yq 'split("; ")' sample.yml
will output
- cat
- meow
- "1"
- ""
- "true"
Given a sample.yml file of:
word
then
yq 'split("; ")' sample.yml
will output
- word
Last modified 6mo ago