Différences

Ci-dessous, les différences entre deux révisions de la page.

--- informatique:jq [03/10/2021 12:01] – créée cyrille
+++ informatique:jq [04/10/2021 08:40] (Version actuelle) – [jq] cyrille
@@ Ligne 1: / Ligne 1: @@
 ====== jq ======
-[[https://github.com/stedolan/jq/|jq]]
+**[[https://stedolan.github.io/jq/|jq]]** a lightweight and flexible command-line JSON processor.
+  * Le [[https://stedolan.github.io/jq/manual/|Manuel]]
   * La [[https://github.com/stedolan/jq/wiki/FAQ|FAQ]]
   * Le [[https://github.com/stedolan/jq/wiki/Cookbook|Cookbook]]
+  * Pour faire des requêtes en ligne : https://jqplay.org
   * [[https://kaijento.github.io/2017/03/20/json-parsing-jq-group_by-max_by-and-sort_by/|JSON parsing: jq group_by() max_by() sort_by()]]
   * [[https://gist.github.com/olih/f7437fb6962fb3ee9fe95bda8d2c8fa4|Processing JSON using jq]]
-  * sur stackoverflow [[https://stackoverflow.com/questions/tagged/jq|jq]]
+  * [[https://stackoverflow.com/questions/tagged/jq|jq sur stackoverflow]]
+===== Play with jq =====
+''members.json'':
+<code>
+[
+ {
+  "member_id": 123,
+  "loans":[
+   {
+    "date": "123",
+    "media": [
+     { "title": "foo" },
+     { "title": "bar" }
+    ]
+   },
+   {
+    "date": "456",
+    "media": [
+     { "title": "foo" }
+    ]
+   }
+  ]
+ },
+ {
+  "member_id": 456,
+  "loans":[
+   {
+    "date": "789",
+    "media": [
+     { "title": "foo"}
+    ]
+   }
+  ]
+ }
+]
+</code>
+==== Howto count occurrence of "grouped by key=value" with jq? ====
+https://stackoverflow.com/questions/69423726/howto-count-occurrence-of-grouped-by-key-with-jq/
+=== Sans group_by ===
+<code bash>
+jq '"foo" as $title | .[] | {
+  id: .member_id,
+  $title,
+  count: [.loans[].media[] | select(.title == $title)] | length
+}' members.json
+</code>
+<code>
+{
+  "id": 123,
+  "title": "foo",
+  "count": 2
+}
+{
+  "id": 456,
+  "title": "foo",
+  "count": 1
+}
+</code>
+=== Avec group_by ===
+<code bash>
+jq  'map(
+         (.member_id) as $m
+        | .loans[].media[]
+        | select(.title=="foo")
+        | {id: $m, title: .title}
+        )
+    |group_by(.id)[]
+    |.[0] + { count: length }
+' members.json
+</code>