Depending on the arguments passed to the Ruby Array#count
method, it can be used in the following cases:
Please note that Array#count
is different from Array#size
and Array#length
methods, which are specifically used for getting the length of an array.
Counting Total Items
When used without arguments, it counts the total number of items in an array:
puts [3, 3, 4, 3, 3, 5, 5].count #=> 7 puts [].count #=> 0
Counting Specific Values
When used with a numeric argument, it counts the number of times the specific value occurs in an array:
puts [3, 3, 4, 3, 3, 5, 5].count(3) #=> 4 puts [].count(3) #=> 0
Conditional Counting
When used with a block, it counts the total number of items in an array that satisfy a condition based on the block:
puts [3, 3, 4, 3, 3, 5, 5].count { | item | item < 4 } #=> 4 puts [].count { | item | item < 4 } #=> 0
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