Collections: ArrayLists and HashMaps by

Collections: ArrayLists and HashMaps by https://padlet.com/skCompSci/collections What is a List and an ArrayList in Java? What is a Map and a HashMap in Java? How are these collections defined and initiliased? en-us 2017-11-17 12:39:21 UTC 2017-11-17 17:22:03 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Folder.png HashMap https://padlet.com/skCompSci/collections/wish/208101381 Have a hashing algorithm to create addresses/keys for elements]]> 2017-11-17 14:02:06 UTC https://padlet.com/skCompSci/collections/wish/208101381 Everything https://padlet.com/skCompSci/collections/wish/208101398 2017-11-17 14:02:07 UTC https://padlet.com/skCompSci/collections/wish/208101398 ArrayLists https://padlet.com/skCompSci/collections/wish/208101541 size is dynamic
takes objects and generics

]]> 2017-11-17 14:02:25 UTC https://padlet.com/skCompSci/collections/wish/208101541 ArrayList https://padlet.com/skCompSci/collections/wish/208101606 2017-11-17 14:02:33 UTC https://padlet.com/skCompSci/collections/wish/208101606 Hash map is the good shit https://padlet.com/skCompSci/collections/wish/208101612 2017-11-17 14:02:34 UTC https://padlet.com/skCompSci/collections/wish/208101612 ArrayLists are dynamic https://padlet.com/skCompSci/collections/wish/208101629 no clue on HashMaps]]> 2017-11-17 14:02:36 UTC https://padlet.com/skCompSci/collections/wish/208101629 https://padlet.com/skCompSci/collections/wish/208101751 Arraylist - like array, but is not fixed in length.
HashMap - a bit like two dimentional array

]]> 2017-11-17 14:02:52 UTC https://padlet.com/skCompSci/collections/wish/208101751 hashmap¿? vcasadoh https://padlet.com/skCompSci/collections/wish/208101791 Hashmap?]]> 2017-11-17 14:02:57 UTC https://padlet.com/skCompSci/collections/wish/208101791 https://padlet.com/skCompSci/collections/wish/208101813 Array lists are sets of values of the same type, with indices. HashMaps are sets of values which can have keys as well]]> 2017-11-17 14:03:00 UTC https://padlet.com/skCompSci/collections/wish/208101813 What is a hash map https://padlet.com/skCompSci/collections/wish/208101814 Sounds yummy]]> 2017-11-17 14:03:00 UTC https://padlet.com/skCompSci/collections/wish/208101814 Hashmaps require a key to indicate which Element you want. Those Keys can be anything and dont follow a certain order https://padlet.com/skCompSci/collections/wish/208101879 2017-11-17 14:03:08 UTC https://padlet.com/skCompSci/collections/wish/208101879 whats a hash map? https://padlet.com/skCompSci/collections/wish/208101913 please someone tell me]]> 2017-11-17 14:03:11 UTC https://padlet.com/skCompSci/collections/wish/208101913 ArrayLists https://padlet.com/skCompSci/collections/wish/208102142 ArrayLists are similar to arrays but have a dynamic size that automatically updates based on the number of elements stored within]]> 2017-11-17 14:03:35 UTC https://padlet.com/skCompSci/collections/wish/208102142 nothing https://padlet.com/skCompSci/collections/wish/208102154 2017-11-17 14:03:37 UTC https://padlet.com/skCompSci/collections/wish/208102154 ArrayList dynamic Array static, .add is life https://padlet.com/skCompSci/collections/wish/208102197 p.s wtf is a hash map please stop this madness]]> 2017-11-17 14:03:41 UTC https://padlet.com/skCompSci/collections/wish/208102197 Arraylists are variables; are classes https://padlet.com/skCompSci/collections/wish/208102208 2017-11-17 14:03:43 UTC https://padlet.com/skCompSci/collections/wish/208102208 https://padlet.com/skCompSci/collections/wish/208102232 ArrayList is a dynamic type of array which doesn't have fixed length. It uses wrappers.

Nothing about hash maps.]]> 2017-11-17 14:03:47 UTC https://padlet.com/skCompSci/collections/wish/208102232 I said a pound of hash is heavier than a pound of feathers!! https://padlet.com/skCompSci/collections/wish/208102276 2017-11-17 14:03:51 UTC https://padlet.com/skCompSci/collections/wish/208102276 arraylists can hold more than one data type https://padlet.com/skCompSci/collections/wish/208102338 2017-11-17 14:04:00 UTC https://padlet.com/skCompSci/collections/wish/208102338 https://padlet.com/skCompSci/collections/wish/208102441 I don’t know what is “HashMaps”]]> 2017-11-17 14:04:10 UTC https://padlet.com/skCompSci/collections/wish/208102441 Array lists https://padlet.com/skCompSci/collections/wish/208102468 Need to be imported before they can work

]]> 2017-11-17 14:04:13 UTC https://padlet.com/skCompSci/collections/wish/208102468 Not enough https://padlet.com/skCompSci/collections/wish/208102548 2017-11-17 14:04:22 UTC https://padlet.com/skCompSci/collections/wish/208102548 Array https://padlet.com/skCompSci/collections/wish/208102553 2017-11-17 14:04:23 UTC https://padlet.com/skCompSci/collections/wish/208102553 420 good shit https://padlet.com/skCompSci/collections/wish/208102593 2017-11-17 14:04:26 UTC https://padlet.com/skCompSci/collections/wish/208102593 https://padlet.com/skCompSci/collections/wish/208102594 2017-11-17 14:04:27 UTC https://padlet.com/skCompSci/collections/wish/208102594 Array list is only one https://padlet.com/skCompSci/collections/wish/208102595 2017-11-17 14:04:27 UTC https://padlet.com/skCompSci/collections/wish/208102595 https://padlet.com/skCompSci/collections/wish/208102637 2017-11-17 14:04:32 UTC https://padlet.com/skCompSci/collections/wish/208102637 https://padlet.com/skCompSci/collections/wish/208102652 Hash maps can be used when dealing with large data]]> 2017-11-17 14:04:34 UTC https://padlet.com/skCompSci/collections/wish/208102652 Arraylist https://padlet.com/skCompSci/collections/wish/208102681 Dynamic, can be transform into array.

]]> 2017-11-17 14:04:38 UTC https://padlet.com/skCompSci/collections/wish/208102681 ArrayList is bad when it comes to deleting/inserting elements https://padlet.com/skCompSci/collections/wish/208102757 2017-11-17 14:04:46 UTC https://padlet.com/skCompSci/collections/wish/208102757 ArrayList https://padlet.com/skCompSci/collections/wish/208102826 2017-11-17 14:04:53 UTC https://padlet.com/skCompSci/collections/wish/208102826 idk https://padlet.com/skCompSci/collections/wish/208139482 2017-11-17 15:10:01 UTC https://padlet.com/skCompSci/collections/wish/208139482 Differences between ArrayLists and Hashmaps https://padlet.com/skCompSci/collections/wish/208139689 Ordering: ArrayLists yes
Hashmaps no
Indexes: ArrayLists yes
Hasmmaps no]]> 2017-11-17 15:10:27 UTC https://padlet.com/skCompSci/collections/wish/208139689 https://padlet.com/skCompSci/collections/wish/208139781 Hashmap larger]]> 2017-11-17 15:10:39 UTC https://padlet.com/skCompSci/collections/wish/208139781 https://padlet.com/skCompSci/collections/wish/208139815 Methods,
The way the data is stored,
Cannot have duplicates

]]> 2017-11-17 15:10:43 UTC https://padlet.com/skCompSci/collections/wish/208139815 hashmaps https://padlet.com/skCompSci/collections/wish/208139829 holds values like an arraylist but every value has a key connected to it.

arraylists can hold duplicate values but hashmaps cannot have duplicates of the key

]]> 2017-11-17 15:10:45 UTC https://padlet.com/skCompSci/collections/wish/208139829 Arraylists hold repeated values https://padlet.com/skCompSci/collections/wish/208139853 This is less efficient when doing operations like quick maffs]]> 2017-11-17 15:10:48 UTC https://padlet.com/skCompSci/collections/wish/208139853 You can delete only one element at a time with the same content where as with hash maps you can delete two elements at the same time https://padlet.com/skCompSci/collections/wish/208139854 2017-11-17 15:10:48 UTC https://padlet.com/skCompSci/collections/wish/208139854 Within an array list of you want to remove a value that has been entered twice it will remove the first value it finds on the list however, within a hashmap it will remove the value no matter where it is stated within the values. https://padlet.com/skCompSci/collections/wish/208139932 2017-11-17 15:10:56 UTC https://padlet.com/skCompSci/collections/wish/208139932 Adding elements https://padlet.com/skCompSci/collections/wish/208139944 .add() - ArrayList
.put() - HashMaps]]> 2017-11-17 15:10:58 UTC https://padlet.com/skCompSci/collections/wish/208139944 Insertion Order https://padlet.com/skCompSci/collections/wish/208139954 ArrayList maintains the insertion order while HashMap doesn’t. ]]> 2017-11-17 15:10:59 UTC https://padlet.com/skCompSci/collections/wish/208139954 2 plus 2 is 4 minus 1 thats 3 quick maths https://padlet.com/skCompSci/collections/wish/208140003 2017-11-17 15:11:04 UTC https://padlet.com/skCompSci/collections/wish/208140003 Keys and Values in hashmaps https://padlet.com/skCompSci/collections/wish/208140042 2017-11-17 15:11:09 UTC https://padlet.com/skCompSci/collections/wish/208140042 hashmaps and arraylist https://padlet.com/skCompSci/collections/wish/208140091 Hashmaps take a key, which has a stored value. Hashmaps accessed via key whereas arraylists accessed thru indes]]> 2017-11-17 15:11:15 UTC https://padlet.com/skCompSci/collections/wish/208140091 You can have the same elements in an arraylist but only unique in the key of hashmaps https://padlet.com/skCompSci/collections/wish/208140107 2017-11-17 15:11:17 UTC https://padlet.com/skCompSci/collections/wish/208140107 https://padlet.com/skCompSci/collections/wish/208140152 Hash map cannot have key duplicates]]> 2017-11-17 15:11:22 UTC https://padlet.com/skCompSci/collections/wish/208140152 Hashmaps are dynamic and can remove multiple values https://padlet.com/skCompSci/collections/wish/208140154 2017-11-17 15:11:22 UTC https://padlet.com/skCompSci/collections/wish/208140154 Array list are longer than hash maps. Hash maps are more suitable to work with large data https://padlet.com/skCompSci/collections/wish/208140158 2017-11-17 15:11:23 UTC https://padlet.com/skCompSci/collections/wish/208140158 Insertion Order https://padlet.com/skCompSci/collections/wish/208140160 ArrayList maintains the insertion order while HashMap doesn’t. ]]> 2017-11-17 15:11:23 UTC https://padlet.com/skCompSci/collections/wish/208140160 kęý https://padlet.com/skCompSci/collections/wish/208140161

]]> 2017-11-17 15:11:23 UTC https://padlet.com/skCompSci/collections/wish/208140161 https://padlet.com/skCompSci/collections/wish/208140214 Hashmaps cannot contain duplicate keys, whereas array lists can contain duplicate values ]]> 2017-11-17 15:11:30 UTC https://padlet.com/skCompSci/collections/wish/208140214 https://padlet.com/skCompSci/collections/wish/208140279 HashMaps as the name says, it will map a KEY , to a specific value, that means that we can bring a value using the key]]> 2017-11-17 15:11:38 UTC https://padlet.com/skCompSci/collections/wish/208140279 hashmaps link keys to values https://padlet.com/skCompSci/collections/wish/208140306 2017-11-17 15:11:40 UTC https://padlet.com/skCompSci/collections/wish/208140306 Pundai https://padlet.com/skCompSci/collections/wish/208140344 2017-11-17 15:11:44 UTC https://padlet.com/skCompSci/collections/wish/208140344 Removal https://padlet.com/skCompSci/collections/wish/208140393 HashMap performes better when it comes to removing elements]]> 2017-11-17 15:11:49 UTC https://padlet.com/skCompSci/collections/wish/208140393 Always display a random list of their elements https://padlet.com/skCompSci/collections/wish/208140407 2017-11-17 15:11:50 UTC https://padlet.com/skCompSci/collections/wish/208140407 Everything up to arraylists sxatzakis https://padlet.com/skCompSci/collections/wish/208140444 casts, .ordinal()...

]]> 2017-11-17 15:11:54 UTC https://padlet.com/skCompSci/collections/wish/208140444 ArrayList vs Hashmaps https://padlet.com/skCompSci/collections/wish/208140452 Ordering: ArrayLists yes
Hashmaps no
Indexes: ArrayLists yes
Hasmmaps no]]> 2017-11-17 15:11:56 UTC https://padlet.com/skCompSci/collections/wish/208140452 Everything https://padlet.com/skCompSci/collections/wish/208140456

]]> 2017-11-17 15:11:56 UTC https://padlet.com/skCompSci/collections/wish/208140456 https://padlet.com/skCompSci/collections/wish/208140579 can inly access stuff using .get in hashmap whereas ]]> 2017-11-17 15:12:10 UTC https://padlet.com/skCompSci/collections/wish/208140579 arraylists allow duplicate elements https://padlet.com/skCompSci/collections/wish/208140629 hashmaps do not allow duplicate keys but do allow duplicate keys ]]> 2017-11-17 15:12:14 UTC https://padlet.com/skCompSci/collections/wish/208140629 Hash maps are more confusing https://padlet.com/skCompSci/collections/wish/208140668 2017-11-17 15:12:18 UTC https://padlet.com/skCompSci/collections/wish/208140668 ArrayLists vs Hashmaps https://padlet.com/skCompSci/collections/wish/208140699 2017-11-17 15:12:22 UTC https://padlet.com/skCompSci/collections/wish/208140699 python>java https://padlet.com/skCompSci/collections/wish/208140754 2017-11-17 15:12:27 UTC https://padlet.com/skCompSci/collections/wish/208140754 Memmory space https://padlet.com/skCompSci/collections/wish/208140759 Memmory space]]> 2017-11-17 15:12:28 UTC https://padlet.com/skCompSci/collections/wish/208140759 Mans not hot https://padlet.com/skCompSci/collections/wish/208140826 2017-11-17 15:12:36 UTC https://padlet.com/skCompSci/collections/wish/208140826 Quick maffs https://padlet.com/skCompSci/collections/wish/208140904 2+2 = 4 -1 = 3]]> 2017-11-17 15:12:44 UTC https://padlet.com/skCompSci/collections/wish/208140904 Hash not hot https://padlet.com/skCompSci/collections/wish/208141299 Array hot]]> 2017-11-17 15:13:30 UTC https://padlet.com/skCompSci/collections/wish/208141299 Misconceptions https://padlet.com/skCompSci/collections/wish/208147450 2017-11-17 15:24:41 UTC https://padlet.com/skCompSci/collections/wish/208147450 https://padlet.com/skCompSci/collections/wish/208147918 What is a hashmap]]> 2017-11-17 15:25:27 UTC https://padlet.com/skCompSci/collections/wish/208147918