# Changes to Context Flow Variable also changes source array it was extracted from

**URL:** <https://discourse.nodered.org/t/changes-to-context-flow-variable-also-changes-source-array-it-was-extracted-from/17070>\
**Category:** General\
**Created:** [24 October 2019 05:49 UTC](https://discourse.nodered.org/t/changes-to-context-flow-variable-also-changes-source-array-it-was-extracted-from/17070 "2019-10-24T05:49:52Z")\
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**Author:** ![IanH](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/ianh/32/95002_2.png) [@IanH](https://discourse.nodered.org/u/IanH)\
**Post date:** [24 October 2019 05:49 UTC](https://discourse.nodered.org/t/changes-to-context-flow-variable-also-changes-source-array-it-was-extracted-from/17070/1 "2019-10-24T05:49:52Z")

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I have found what I think is anomalous behavior (from what I expected) when changing an element in a context Flow Object Variable that was itself extracted as one object in an array of objects from a object in Context Flow variables.

To explain further as demonstrated in this Flow. We create a array of JSON objects `flow.sZones`. From that we extract one object from the array into `flow.sZone = flow.sZones.Zone[4]`.

Now I change one element in `flow.sZone` to a new value but it also changes the corresponding value in `flow.sZones`, it even gets the right element. As demonstrated in flow below I change `flow.sZone.Value = 23` but this also changes `flow.sZones.Zone[4].Value` to 23.  
It is like `flow.sZone` is not a separate variable, but a pointer to `flow.sZones.Zone[4]`

`[{"id":"97d95e4.9c88aa","type":"inject","z":"c3c6cf1d.d7dd1","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":true,"onceDelay":0.1,"x":124.5,"y":60,"wires":[["50e4695e.fd9688"]]},{"id":"50e4695e.fd9688","type":"change","z":"c3c6cf1d.d7dd1","name":"Reset Array","rules":[{"t":"set","p":"sZones","pt":"flow","to":"{\"Zone\":[{\"Number\":0,\"Name\":\"Zero\",\"Description\":\"D Zero\",\"Value\":4},{\"Number\":1,\"Name\":\"One\",\"Description\":\"D One\",\"Value\":5},{\"Number\":2,\"Name\":\"Two\",\"Description\":\"D Two\",\"Value\":6},{\"Number\":3,\"Name\":\"Three\",\"Description\":\"D Three\",\"Value\":7},{\"Number\":4,\"Name\":\"Four\",\"Description\":\"D Four\",\"Value\":8},{\"Number\":5,\"Name\":\"Five\",\"Description\":\"D Five\",\"Value\":9},{\"Number\":6,\"Name\":\"Six\",\"Description\":\"D Six\",\"Value\":10},{\"Number\":7,\"Name\":\"Seven\",\"Description\":\"D Seven\",\"Value\":11}]}","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":326.5,"y":60,"wires":[["9497f5fa.3bb0e8"]]},{"id":"9497f5fa.3bb0e8","type":"change","z":"c3c6cf1d.d7dd1","name":"","rules":[{"t":"set","p":"sZone","pt":"flow","to":"sZones.Zone[4]","tot":"flow"},{"t":"set","p":"sZone.Value","pt":"flow","to":"23","tot":"num"},{"t":"set","p":"sZones","pt":"msg","to":"sZones","tot":"flow"},{"t":"set","p":"sZone","pt":"msg","to":"sZone","tot":"flow"}],"action":"","property":"","from":"","to":"","reg":false,"x":637,"y":60,"wires":[["827be915.44bbc8"]]},{"id":"827be915.44bbc8","type":"debug","z":"c3c6cf1d.d7dd1","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":801.5,"y":60,"wires":[]}]`

Latest Nod-Red (1.02) running on up to date W10 (my Sandpit). Context Variables in memory only

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