Add Get A Slice Of The Ends Of An Array as a jq TIL

jq/get-a-slice-of-the-ends-of-an-array.md

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+# Get A Slice Of The Ends Of An Array
+
+[`jq`](https://jqlang.github.io/jq/) has an array slice syntax that allows us
+to grab a subset of values from an array. The general form of this syntax is
+`[n:m]` where `n` is the index of the start of our slice (inclusive) and `m` is
+the index of the end of our slice (non-inclusive).
+
+If we omit the `n`, it defaults to `0`, or the start of the array. Similarly,
+if we omit the `m`, it defaults to the end of the list.
+
+Knowing that, we can grab the first few elements of the list like so:
+
+```bash
+❯ echo '["a","b","c","d","e","f","g"]' | jq '.[:3]'
+[
+  "a",
+  "b",
+  "c"
+]
+```
+
+We can also use a negative index value to count back from the end of the array.
+This allows us to grab a slice from some point relative to the end of the list.
+Instead of having to compute it based on knowing the length of the array.
+
+Knowing that, we can grab the last few elements of the list like so:
+
+```bash
+❯ echo '["a","b","c","d","e","f","g"]' | jq '.[-3:]'
+[
+  "e",
+  "f",
+  "g"
+]
+```
+
+[source](https://jqlang.github.io/jq/manual/#array-string-slice)