LIFO

push
: a command to add a new item to the end of an array.
pop
: a command to remove the last item from the end of an array.
shift
: a command to remove the first item from the front of an array.
unshift
: a command to insert a new item at the front of an array.
LIFO
: Last in, first out. When a sequence of things are added to a list, the
most recent (last) item is the first one we will consider.
stack
: a word to describe a list used in a last-in, first-out way.
FIFO
: First in, first out. When a sequence of things are added to a list, the
oldest (first) item is the first one we will consider.
queue
: a word to describe a list used in a first-in, first-out way. Consider
people waiting in line for movie tickets. The first person in line should be
the first person to be able to purchase tickets.
index
: a number that tells which slot of the array is being considered.
Numbering starts with zero at the front and counts up. Numbering from
the back starts at -1 and counts down using negative numbers.
foreach
: a type of loop that avoids index numbers while still giving access
to each array element in turn.
split
: a command to separate a string on certain boundaries thus creating
an array.
join
: a command to combine the elements of an array thus creating a string.