Get single item from List<HashMap<String, String>>

Question

I am modifying someone else code. I have a variable of type List<HashMap<String, String>>

List<HashMap<String, String>> lst

I tried to use get the item single value by using

lst[0,1]
lst[0][1]
lst.get(0)[1]
lst.get(0)(1)
lst.get(0)("ID")

but non works.

how to get a single item value?

    List<HashMap<String, String>> lst = null;

    try{
        lst = myXmlParser.detparse(reader);
    }catch(Exception e){
        Log.d("Exception", e.toString());
    }

use list.get(index); it will return you an object of type HashMap<String,String> index here is an int of your choice. — SMR
– SMR, Commented Jul 7, 2014 at 9:43
I used list.get(index) but it will not return a single value it will return a list of 4 items — asmgx
– asmgx, Commented Jul 7, 2014 at 9:46
Not sure what the code producing the List<HashMap<String,String>> by getparse is meant to say in connection with the question "how to get a single item". — laune
– laune, Commented Jul 7, 2014 at 9:57

André Stannek · Accepted Answer · 2014-07-07 09:46:44Z

1

You should read the documentation of List and Map (respective HashMap) to see how to use them.

Since your List contains Map you'll have to get a Map using the List operations and then get the elements from that Map using the Map operations:

HashMap<String, String> firstMap = lst.get(0);
String someEntry = firstMap.get("key");

answered Jul 7, 2014 at 9:46

André Stannek

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Stu Whyte · Accepted Answer · 2014-07-07 09:43:50Z

0

HashMap<String, String> firstEntryInList = list.get(0);

Where '0' is the index.

answered Jul 7, 2014 at 9:43

Stu Whyte

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Vinay Veluri · Accepted Answer · 2014-07-07 09:45:08Z

0

Why not using index of list...

HashMap<String, String> entry = lst.get(0);

answered Jul 7, 2014 at 9:45

Vinay Veluri

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2 Comments

Vinay Veluri Over a year ago

@DownVoter, Can it be commented, why to down vote? To return an element from a list using indexes - use get(index) is the suggestion and its appropriate to the question.

laune Over a year ago

I think that a rather weird one was downvoting each and every answer on this Q. I got credited +8, which looks like one up and one down, others may have experienced similar.

laune · Accepted Answer · 2014-07-07 09:55:57Z

0

Accessor methods must be applied from outer to inner. If you have a

List<Whatever> lst

you use

lst.get(0)

to retrieve the first element in the list. If Whatever is in turn an aggregate, you apply the appropriate accessor on the returned value:

List<Map<String,String>> lst

and to get the string that's mapped via "somekey":

lst.get(0).get("somekey")

Now, this will get you a String, and this has accessors, too, eg. for accessing a single character:

lst.get(0).get("somekey").charAt(0)

This is "the first character of the string mapped with key "somekey" in the first hash map of the list lst".

answered Jul 7, 2014 at 9:55

laune

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