Using GPT-3 to figure out jq recipes

Author: simonw

gpt3/jq.md

@@ -0,0 +1,78 @@
+# Using GPT-3 to figure out jq recipes
+
+I like [jq](https://stedolan.github.io/jq/), but I always have to think pretty hard about how to construct the right syntax for it.
+
+Here's how I used the [GPT-3 playground](https://simonwillison.net/2022/Jun/5/play-with-gpt3/) to solve a simple `jq` problem.
+
+I wanted to sum up the total number of comments in JSON that looks like this (truncated example):
+
+```json
+[
+    {
+        "id": "31195431",
+        "title": "Automatically filing issues when tracked file content changes",
+        "url": "https://simonwillison.net/2022/Apr/28/issue-on-changes/",
+        "dt": "2022-04-28T17:29:37",
+        "points": 14,
+        "submitter": "simonw",
+        "commentsUrl": "https://news.ycombinator.com/item?id=31195431",
+        "numComments": 4
+    },
+    {
+        "id": "31185496",
+        "title": "Parallel SQL Queries in Datasette",
+        "url": "https://simonwillison.net/2022/Apr/27/parallel-queries/",
+        "dt": "2022-04-27T20:39:50",
+        "points": 1,
+        "submitter": "frogger8",
+        "commentsUrl": "https://news.ycombinator.com/item?id=31185496",
+        "numComments": 3
+    }
+]
+```
+The first prompt I tried was:
+
+```
+# Use jq to calculate the sum of the num field in each object in this array:
+
+echo '[
+  {"num": 1},
+  {"num": 2}
+]' | jq
+```
+I hinted at how I wanted to do this by piping to `jq` but without any argument.
+
+GPT-3 completed that to:
+
+```
+echo '[
+  {"num": 1},
+  {"num": 2}
+]' | jq 'reduce .[] as $item (0; . + $item.num)'
+```
+... then a bunch more output that gave further examples, which I ignored
+
+This is good - that solution works! Here's what happens when I run it:
+
+```
+~ % echo '[
+  {"num": 1},
+  {"num": 2}
+]' | jq 'reduce .[] as $item (0; . + $item.num)'
+3
+```
+But I'm not a big fan of `reduce` in general - I always have to think a bit about what it's actually doing.
+
+So I added a follow-up prompt:
+
+```
+Now do that without using reduce:
+```
+And GPT-3 replied:
+```
+echo '[
+  {"num": 1},
+  {"num": 2}
+]' | jq  '. | map(.num) | add'
+```
+This is the exact solution I was looking for.