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Count number of values in array with a given value
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Get the last item in an array
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How to check if an array element exists?
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Algorithm: efficient way to remove duplicate integers from an array
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Determining the number of occurrences of each unique element in a vector
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How to find the unique elements in an array in Ruby
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Java: Detect duplicates in ArrayList?
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Counting inversions in an array
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Checking if an array has some items in coffeescript
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Specifying an array with a specific number of copies of two elements
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Detect a number of specific items in the inventory
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How do I count unique values inside a list
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How to count specific items in column?
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Is there a way to view the number of unique views for a question on a mobile device?
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Selecting Unique Elements From a List in C#