This week's book giveaway is in the Artificial Intelligence forum.
We're giving away four copies of Pragmatic AI and have Noah Gift on-line!
See this thread for details.
Win a copy of Pragmatic AI this week in the Artificial Intelligence forum!
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
programming forums Java Mobile Certification Databases Caching Books Engineering Micro Controllers OS Languages Paradigms IDEs Build Tools Frameworks Application Servers Open Source This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
  • Jeanne Boyarsky
  • Liutauras Vilda
  • Campbell Ritchie
  • Tim Cooke
  • Bear Bibeault
  • Paul Clapham
  • Junilu Lacar
  • Knute Snortum
Saloon Keepers:
  • Ron McLeod
  • Ganesh Patekar
  • Tim Moores
  • Pete Letkeman
  • Stephan van Hulst
  • Carey Brown
  • Tim Holloway
  • Joe Ess

Map with Arraylist as value  RSS feed

Ranch Hand
Posts: 279
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I have files with names such as


Double underscore (__), differnetiates differnet parts of the file name.
Part1 --> value before first __ (example, address_change)
Part2 --> value after first __ and before second__ (example, customer_request, corres_in)
Part3 --> value after second __ (example, 111, 222)

I am able to read the file names and get the values for Part1, Part2 and Part3.
The file names with similar Part3 need to be handled in the same way. Example, files 1 and 2, need to be handled differently from files 3,4 and 5.

So to distinguish files based on Part3, I want to create a datastructure such as
Map<String, <List<String>>

The Map which has first key as 111 and value is an Arraylist containing address_change__customer_request__111.pdf and address_change__corres_in__111.pdf
Second key in the Map is 222 and value is an ArrayList containing values address_change__signature_card__222.pdf, address_change__customer_request__222.pdf and address_change__corres_in__222.pdf

Please let me know how can this be achieved.

Trying to do something like this

Posts: 59792
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
You mean you want to use one part of the String as a key to get a List<String> as the value and add the remainder of the String to the List?
You just need to make sure to put a new List<String> into the Map if it doesn't contain that particular key.

That's what you have to do. Go through the Map interface API documentation and all the functionality you need is there.
It is sorta covered in the JavaRanch Style Guide.
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!