spaceballs!!!!!
Ahhh great movie
Programming and robotics go together like peas and carrots!
Also search youtube for a playlist called Machine Learning Summer School 2014. Gitter does weird things to playlist links.
I'm stuck on the "Steamroller Challenge". I was wondering if someone could take a look at this. Currently, it seems to break the browser when I run it. Infinite loop possibly?
function steamrollArray(arr) {
var answer = [];
for(i=-1; i<arr.length; i++){
//empty array case
if(arr.length===0){
return answer;
}
if(i===-1){
i++;
}
//if the current array index does
//not contain another array
if(!Array.isArray(arr[i])){
answer.push(arr[i]);
}
//if the current array has a
//sub-array use recursion
if(Array.isArray(arr[i])){
answer = steamrollArray2(arr[i], answer);
}
}
return answer;
}
//I created a second function just like the first
//because I don't want to re-initialize
//answer = []; and FCC doesn't like global
//variables
function steamrollArray2(arr, answer) {
for(i=-1; i<arr.length; i++){
//empty array case
if(arr.length===0){
return answer;
}
if(i===-1){
i++;
}
//if the current array index does
//not contain another array
if(!Array.isArray(arr[i])){
answer.push(arr[i]);
}
//if the current array has a sub-array
//use recursion to.
if(Array.isArray(arr[i])){
steamrollArray2(arr[i],answer);
}
}
return answer;
}
steamrollArray([1, [2], [3, [[4]]]]);
/*
steamrollArray([[["a"]], [["b"]]]) should return ["a", "b"].
steamrollArray([1, [2], [3, [[4]]]]) should return [1, 2, 3, 4].
steamrollArray([1, [], [3, [[4]]]]) should return [1, 3, 4].
steamrollArray([1, {}, [3, [[4]]]]) should return [1, {}, 3, 4].
*/
I've already put together some example code on an alternative method for checking
ah nevermind I've figured it out
// for your loop statements use var i = -1 when initializing the index
// use this instead
for(var i = -1; i < arr.length; i++) { /* your loop code */ }
// otherwise i is a global variable and your recursive functions keep overwriting it
// so after it returns from one of them, it goes back to -1 every time
// also I'm typing up an alternative way to check for array length because looping through an array
// starting at index of -1 is confusing and not clear, therefore it's a bad practice
your logic is sound though
Thanks @Lilyheart for taking a look at it as well!
Here is what I had typed up for suggestions on how to make your code clearer
function steamrollArray(arr) {
var answer = [];
// steamrollArray2 is redundant
// here's how to avoid writing the code twice:
//
// instead we can define a function instead here rather than the global
// namespace and then it avoids writing the same code twice
//
// notice it's doesn't take the answer as an argument
// that's because it will have access to it since it's being defined inside
// the steamrollArray function
var recursiveSteamrollArray = function(arr) {
// starting at index of -1 makes your code unclear, and therefore is
// a bad practice, even though your logic is correct
//
// to avoid the case of arr.length being 0 we can check before enterting
// the for loop
if (arr.length === 0) {
return answer;
}
for (var i = 0; i < arr.length; i++) {
// no need to use if (i === -1) { i++; } anymore
//if the current array index does
//not contain another array
if (!Array.isArray(arr[i])) {
answer.push(arr[i]);
}
//if the current array has a
//sub-array use recursion
if (Array.isArray(arr[i])) {
answer = recursiveSteamrollArray(arr[i], answer);
}
}
return answer;
};
// recursiveSteamrollArray was defined but not called yet
// so let's call the function and then return answer
recursiveSteamrollArray(arr);
return answer;
}
console.log(steamrollArray([1, [2],
[3, [
[4]
]]
]));function steamrollArray(arr) {
var flatArr = [];
for (var i = 0; i < arr.length; i++) {
if (Array.isArray(arr[i])) {
var tempArr = steamrollArray(arr[i]);
for (var j = 0; j < tempArr.length; j++) {
flatArr.push(tempArr[j]);
}
} else {
flatArr.push(arr[i]);
}
}
return flatArr;
}
Sure! In steamroll, if you didn't have the test cases, you'd have no idea how far deep the arrays go. Maybe 2, Maybe 12. Like in factorial, you may only be doing ^6 or ^106. When writing the code, you don't know how deep you will need to go. Factorial you could for loop, but in steamroll not so much as in factorial you know from the onset how many. But in steamroll, until the code fully dissects the array, you'd never know how many dimensions the array has.
Hopefully that makes sense. Sleep was not so grand.