Is it possible to check if an area contains only one entity with command blocks. I've tried /testfor, but it activates the redstone for one person, even if there are more...


/testfor @e will output a signal strength based on how many entities it finds. For example, if 5 entities are found, the signal strength outputted will travel 5 blocks.

To test for exactly one entity, you can do something like this with and add on an AND gate:

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Alternatively, you can use another command block with the 'testforblock' command in it, testing for if the first command block has succeeded exactly once. The setup should look something like:

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/testforblock X Y Z command_block 1 {SuccessCount:1}

Where X Y Z are the coordinates of the first command block, and the comparator should come off of this second command block.

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  • So if I add an and gate it will find only one player and no more? – Jacques Marais May 17 '15 at 16:44
  • @user3189338 Yep. The repeater activates when there's one player, and the torch deactivates when there's two players, so both are on only when there's exactly one player. – SirBenet May 17 '15 at 16:46
  • One more question, if I want to check that the players are between specific bounds, how would I do that? – Jacques Marais May 17 '15 at 16:48
  • There's probably a way of doing this without the use of redstone dust, since redstone dust is evil when used with command blocks. – MBraedley May 17 '15 at 17:01
  • @user3189338 Put the bounds in the @e selector arguments. – SirBenet May 17 '15 at 17:35

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