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Below are the Big O performance of common functions of different Java Collections.
List | Add | Remove | Get | Contains | Next | Data Structure
---------------------|------|--------|------|----------|------|---------------
ArrayList | O(1) | O(n) | O(1) | O(n) | O(1) | Array
LinkedList | O(1) | O(1) | O(n) | O(n) | O(1) | Linked List
CopyOnWriteArrayList | O(n) | O(n) | O(1) | O(n) | O(1) | Array
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ZwodahS / copy_redis_key.sh
Created March 1, 2016 06:07
copy a redis db key to another place (use MIGRATE COPY for v3.0<= redis)
#!/bin/bash
# source http://stackoverflow.com/questions/23222616/copy-all-keys-from-one-db-to-another-in-redis
#set connection data accordingly
source_host=localhost
source_port=6379
source_db=1
target_host=localhost
target_port=6379
target_db=2