pq is a Python command-line JSON processor
Project description
pq-json
pq is a Python command-line JSON processor - almost like (atleast inspired by 🐶️) jq, but using Python focusing on simplicity and convenience with familiar syntax.
Install
pip install pq-json
Here is a simple example for parsing JSON. Output from pq is pretty printed using Rich.
$ echo '{"text": "Text here", "header": "Header", "list": [1,2,3]}' | pq
{
"text": "Text here",
"header": "Header",
"list": [
1,
2,
3
]
}
Filters
The processing is handled with filters, like in jq. j represents the current input object in a filter.
$ echo '{"example": "data", "nothing": "interesting"}' | pq "j['example']"
"data"
$ echo '{"example": "data", "nothing": "interesting"}' | pq "j['example']"
"data"
As default, None will not be passed.
$ echo '{"example": "data", "nothing": "interesting"}' | pq "j.get('nada')"
List slicing
JSON arrays are converted to Python list.
$ echo '[{"name": "eric", "age": 22}, {"name": "daniel", "age": 44}]' | pq "j[0]"
{
"name": "eric",
"age": 22
}
$ echo '[{"name": "eric", "age": 22}, {"name": "daniel", "age": 44}]' | pq "j[-1]"
{
"name": "daniel",
"age": 44
}
An array always iterates to the next filter. Here we are using the slice symbol [:] to highlight that we are working with an array.
$ echo '[{"name": "eric", "age": 22}, {"name": "daniel", "age": 44}]' | pq "j[:]"
{
"name": "eric",
"age": 22
}
{
"name": "daniel",
"age": 44
}
Want to send the full array to the next filter? Wrap array around []
brackets like:
$ echo '[1,2,3,4,5]' | pq "[j[:]]"
[
1,
2,
3,
4,
5
]
Pipes
Pipes let you chain multiple filters by produce output to the filter to the right of the pipe. Under the hood a pipeline is a chain of generators. An array will for example yield multiple elements to the right.
input:
["a", "b", "c", "d"]
pq "j[0:2] | j.upper()"
| |
filter1 filter2
produces the following result:
"A"
"B"
In this case, the expression j.upper() will be run each time.
j[0] -> "a".upper() -> "A"
j[1] -> "b".upper() -> "B"
Another example:
$ echo '[1,2,3,4,5,6,7,8,9]' | pq 'j[:] | j**2+50'
51
54
59
66
75
86
99
114
131
Array constructs
Above example outputs a list of integers. It's possible to wrap it all into a single array by using [] around the full expression.
$ echo '[1,2,3,4,5,6,7,8,9]' | pq '[j[:] | j**2+50]'
[51, 54, 59, 66, 75, 86, 99, 114, 131]
Object constructs
$ echo '{"name":"jan", "age":4, "parents": ["lisa", "dan"]}' | pq '{"name": j["name"], "parents": j["parents"]}'
{
"name": "jan",
"parents": [
"lisa",
"dan"
]
}
Other examples
We can easily use built-in functions in Python
$ echo "[1,2,3,4,5,6]" | pq 'sum(j) | {"total": j}'
{
"total": 21
}
Project details
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