How to manipulate a jq output using bash? - bash

Question

I have the following jq code snippet:
https://jqplay.org/s/QzOttRHoz1
I want to loop each element from the result array using bash such as the pseudo code shows:
#!/bin/bash
foreach result
print "My name is {name}, I'm {age} years old"
print "--"
The result would be:
My name is A, I'm 1 years old.
---
My name is B, I'm 2 years old.
---
My name is C, I'm 3 years old.
---
Of course this is a trivial example just to clarify that my goal is to manipulate each array from the jq result individually.
Any suggestions on how to write the pseudo code into valid bash statements?

Answer 1

Saving the json:
{
"Names": [
{ "Name": "A", "Age": "1" },
{ "Name": "B", "Age": "2" },
{ "Name": "C", "Age": "3" }
]
}
as /tmp/input.txt I can run:
</tmp/input.txt jq --raw-output 'foreach .Names[] as $name ([];[];$name | .Name, .Age )' \
| while read -r name && read -r age; do
printf "My name is %s, I'm %d years old.\n" "$name" "$age";
printf -- "--\n";
done
The --raw-output with | .Name, .Age just prints two lines per .Names array member, one with name and another with age. Then I read two lines at a time with while read && read and use that to loop through them.
If you rather have:
["A","1"]
["B","2"]
["C","3"]
that's sad, the best would be to write a full parser that would take strings like "\"" into account. Anyway then you can:
</tmp/input2.txt sed 's/^\[//;s/\]$//;' \
| while IFS=, read name age; do
name=${name%\"};
name=${name#\"};
age=${age%\"};
age=${age#\"};
printf "My name is %s, I'm %d years old.\n" "$name" "$age";
printf -- "--\n";
done
The first sed removed the leading and enclosing [ and ] in each line. Then I read two strings separated by , (so vars like "a,b","c,d" will be read incorrectly). Then these two strings are stripped of leading and enclosing ". Then the usuall printf is used to output the result.

Answer 2

I have a written a simple script to achieve what you need:
My Json file test.json which is similar to your snippet:
{
"Names": [
{ "Name": "A", "Age": "1" },
{ "Name": "B", "Age": "2" },
{ "Name": "C", "Age": "3" }
]
}
My script:
#!/bin/bash
for i in $(cat test.json | jq -r '.Names[] | #base64'); do
_jq() {
echo ${i} | base64 --decode | jq -r ${1}
}
echo "My Name is $(_jq '.Name'), I'm $(_jq '.Age') years old"
done

Answer 3

Note that foreach .Names[] as $name ([];[];$name | .Name, .Age )
can be simplified to:
.Names[] | ( .Name, .Age )
or even in this specific case to:
.Names[][]
or for that matter to:
.[][][]
The important point, however, is that foreach is not needed to achieve simple iteration.