peek | R Documentation |
Try to access first or last element and return some default value if not found.
In contrast to [at2()]
, this function provides a less stricter element
access, that is, it remains valid even if peeked elements don't exist.
peekleft(x, default = NULL) peek(x, default = NULL) ## S3 method for class 'Deque' peek(x, default = NULL) ## S3 method for class 'Deque' peekleft(x, default = NULL)
x |
a |
default |
value to be returned if peeked value does not exist. |
peek
peek at last element of a Deque
.
peekleft
peek at first element of a Deque
.
The first (peekleft
) or last (peek
) element.
at2()
for strict element extraction
# Deque d = deque(1, 2, 3) peek(d) peekleft(d) peek(deque()) peek(deque(), default = 0) peekleft(deque(), default = 0)
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