Okay so let's run through some javascript arrays.
I'm going to try and cover some of the more useful functions in array manipulation.
PUSH & POP
~ works with the END of the array
PUSH
//push() appends one or more items to the end of the array
v.push("f");
console.log(v.length); // 6
console.log(v[5]); // f
And for your info push could also be achieved by
v[v.length] = "f"
Index 0 |
Index 1 |
Index 2 |
Index 3 |
Index 4 |
Index 5 |
a |
b |
c |
d |
e |
f |
To add multiple elements
v.push("g","h","i");
POP
console.log(v.length); // 6
console.log(v[v.length]); // f
v.pop(); // f
console.log(v.length); // 5
console.log(v[v.length]); // e
Index 0 |
Index 1 |
Index 2 |
Index 3 |
Index 4 |
a |
b |
c |
d |
e |
//pop() on an empty array returns undefined
UNSHIFT & SHIFT
~ works with the START of the array
UNSHIFT
v.unshift("f"); //prepends one or more items to the start of the array
//v.unshift("f","o","o");
console.log(v.length); // 6
console.log(v[0]); // f
Index 0 |
Index 1 |
Index 2 |
Index 3 |
Index 4 |
Index 5 |
f |
a |
b |
c |
d |
e |
SHIFT
console.log(v.length); // 6
console.log(v[0]); // f
//shift() returns the first item from the array and shrinks it
v.shift(); // f
console.log(v.length); // 5
console.log(v[0]); // a
Index 0 |
Index 1 |
Index 2 |
Index 3 |
Index 4 |
a |
b |
c |
d |
e |
Merging arrays
Concat
is used to join two or more arrays.
var tail = ["x","y","z"];
var num = ["1","2","3"];
//concat() returns an array of the joined arrays
var v2 = v.concat(tail, num); //["a","b","c", "d","e","x","y","z","1","2","3"]
console.log(v.length); // 5
console.log(v2.length); // 11
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
a |
b |
c |
d |
e |
x |
y |
z |
1 |
2 |
3 |
Well I think that's me done for a while.
Till next time kids.