cover?

        # Range.cover?

(from ruby core)
---
    cover?(object) -> true or false
    cover?(range) -> true or false

---

Returns `true` if the given argument is within `self`, `false`
otherwise.

With non-range argument `object`, evaluates with `<=` and `<`.

For range `self` with included end value (`#exclude_end? == false`),
evaluates thus:

    self.begin <= object <= self.end

Examples:

    r = (1..4)
    r.cover?(1)     # => true
    r.cover?(4)     # => true
    r.cover?(0)     # => false
    r.cover?(5)     # => false
    r.cover?('foo') # => false

    r = ('a'..'d')
    r.cover?('a')     # => true
    r.cover?('d')     # => true
    r.cover?(' ')     # => false
    r.cover?('e')     # => false
    r.cover?(0)       # => false

For range `r` with excluded end value (`#exclude_end? == true`),
evaluates thus:

    r.begin <= object < r.end

Examples:

    r = (1...4)
    r.cover?(1)     # => true
    r.cover?(3)     # => true
    r.cover?(0)     # => false
    r.cover?(4)     # => false
    r.cover?('foo') # => false

    r = ('a'...'d')
    r.cover?('a')     # => true
    r.cover?('c')     # => true
    r.cover?(' ')     # => false
    r.cover?('d')     # => false
    r.cover?(0)       # => false

With range argument `range`, compares the first and last elements of
`self` and `range`:

    r = (1..4)
    r.cover?(1..4)     # => true
    r.cover?(0..4)     # => false
    r.cover?(1..5)     # => false
    r.cover?('a'..'d') # => false

    r = (1...4)
    r.cover?(1..3)     # => true
    r.cover?(1..4)     # => false

If begin and end are numeric, #cover? behaves like #include?

    (1..3).cover?(1.5) # => true
    (1..3).include?(1.5) # => true

But when not numeric, the two methods may differ:

    ('a'..'d').cover?('cc')   # => true
    ('a'..'d').include?('cc') # => false

Returns `false` if either:

*   The begin value of `self` is larger than its end value.
*   An internal call to `<=>` returns `nil`; that is, the operands are
    not comparable.


Related: Range#include?.