how to delete double values in array?

I've got an array like this one:

arrayname[1] = "jacob";
arrayname[2] = "peter";
arrayname[3] = "jacob";
arrayname[4] = "nicholas";

I want to remove the double jacob 开发者_Python百科so it will be like

arrayname[1] = "jacob";
arrayname[2] = "peter";
arrayname[3] = "nicholas";

How do I do that?

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array_unique()

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$array = array_unique($array);