用jq模糊匹配字符串

Question

Let's say I have some JSON in a file, it's a subset of JSON data extracted from a larger JSON file - that's why I'll use stream later in my attempted solution - and it looks like this:

[
{"_id":"1","@":{},"article":false,"body":"Hello world","comments":"3","createdAt":"20201007200628","creator":{"id":"4a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"mkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"},
{"_id":"2","@":{},"article":false,"body":"Goodbye world","comments":"3","createdAt":"20201007200628","creator":{"id":"4a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"mkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"}
],
[
{"_id":"55","@":{},"article":false,"body":"Hello world","comments":"3","createdAt":"20201007200628","creator":{"id":"3a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"jkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"},
{"_id":"56","@":{},"article":false,"body":"Goodbye world","comments":"3","createdAt":"20201007200628","creator":{"id":"3a7ba8fd719d43598b977dd548eed6aa","bio":"","blocked":false,"followed":false,"human":false,"integration":false,"joined":"20201007200628","muted":false,"name":"mkscott","rss":false,"private":false,"username":"jkscott","verified":false,"verifiedComments":false,"badges":[],"score":"0","interactions":258,"state":1},"depth":"0","depthRaw":0,"hashtags":[],"id":"2d4126e342ed46509b55facb49b992a5","impressions":"3","links":[],"sensitive":false,"state":4,"upvotes":"0"}
]

It describes 4 posts written by 2 different authors, with unique _id fields for each post. Both authors wrote 2 posts, where 1 says "Hello World" and the other says "Goodbye World".

I want to match on the word "Hello" and return the _id only for fields containing "Hello". The expected result is:

1
55

The closest I could come in my attempt was:

jq -nr --stream '
fromstream(1|truncate_stream(inputs))
| select(.body %like% "Hello")
| ._id
' <input_file

Answer 1

Assuming the input is modified slightly to make it a stream of the arrays as shown in the Q:

jq -nr --stream '
  fromstream(1|truncate_stream(inputs))
  | select(.body | test("Hello"))
  | ._id
'

produces the desired output.

test uses regex matching. In your case, it seems you could use simple substring matching instead.

Handling extraneous commas

Assuming the input has commas between a stream of valid JSON exactly as shown, you could presumably use sed to remove them first.

Or, if you want an only-jq solution, use the following in conjunction with the -n, -r and --stream command-line options:

def iterate:
  fromstream(1|truncate_stream(inputs?))
  | select(.body | test("Hello"))
  | ._id,
    iterate;


iterate

(Notice the "?".)

Answer 2

The streaming parser (invoked with --stream) is usually not needed for the kind of task you describe, so in this response, I'm going to assume that the following (or a variant thereof) will suffice:

.[]
| select( .body | test("Hello") )._id

This of course assumes that the input is valid JSON.

Handling comma-delimited JSON

If your input is a comma-delimited stream of JSON as shown in the Q, you could use the following in conjunction with the -n command-line option:

# This is a variant of the built-in `recurse/1`:
def iterate(f): def r: f | (., r); r;

iterate( inputs? | .[] | select( .body | test("Hello") )._id )

Please note that this assumes that whatever occurs on a line after a delimiting comma can be ignored.