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docs/lib3x-hashmap_keys.md

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+# hashmap_keys
+
+Returns a list containing all keys in a [util/map/hashmap](https://openhome.cc/eGossip/OpenSCAD/lib3x-hashmap.html). 
+
+**Since:** 3.0
+
+## Parameters
+
+- `map` : The map.
+
+## Examples
+
+    use <util/map/hashmap.scad>;
+    use <util/map/hashmap_keys.scad>;
+
+    m = hashmap([["k1", 10], ["k2", 20], ["k3", 30]]);
+
+    echo(hashmap_keys(m));    // a list contains "k1", "k2", "k3"