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Convert ArrayList(Hashmap<String,String>) to some Arraylists


Convert ArrayList(Hashmap<String,String>) to some Arraylists

By : varin
Date : November 20 2020, 04:01 AM
may help you . I have an ArrayList(Hashmap) named users and each Hashmap contains the profile of a user such as name,id,phone, etc... , You can write such a function with Streams:
code :
public static List<String> getPropertyList(List<Map<String,String>> users, String key)
{
    return users.stream()
                .map(m -> m.get(key))
                .collect(Collectors.toList());
}
List<String> userIds = getPropertyList(users,"id");
List<String> userNames = getPropertyList(users,"name");
...
public static List<String> getPropertyList(List<Map<String,String>> users, String key)
{
    List<String> result = new ArrayList<String>();
    for (Map<String,String> map : users) {
        result.add(map.get(key));
    }
    return result;
}


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Want to convert ArrayList<HashMap<String, Object>> to string

Want to convert ArrayList<HashMap<String, Object>> to string


By : Dan
Date : March 29 2020, 07:55 AM
wish of those help if you want to keep the ArrayList> you have to create a new String[] this way:
code :
String[] urls = new String[MyArrList.size()];
for(int i=0; i<MyArrList.size(); i++){
   urls[i] = MyArrList.get(i).get("cardimage");
}
How to Convert ArrayList<HashMap<String, String>> to a StringArray?

How to Convert ArrayList<HashMap<String, String>> to a StringArray?


By : Tony
Date : March 29 2020, 07:55 AM
This might help you I want to store a String array in the database, but I got values from another activity as an ArrayList>. How should I convert this ArrayList into a String array? , Simply use:
code :
String[] strArray = new String[urArrayList.size()];
strArray = urArrayList.toArray(strArray);
int i = 0;
String strArr[] = new String[urArrayList.size()];
for (HashMap<String, String> hashMap : urArrayList) {
 for (String value : hashMap.values()) {
    strArr[i] = value ;
    i++;

 }
}
Android inserting multiple single item into a ArrayList<HashMap<String, String>> from HashMap<String, Str

Android inserting multiple single item into a ArrayList<HashMap<String, String>> from HashMap<String, Str


By : Anderson
Date : March 29 2020, 07:55 AM
wish of those help I'm trying to insert multiple single item into an ArrayList> Here is my code: , Try taking for loop:
code :
for (int i = 0; i<multipleHours.length;i++){
HashMap<String, String> alarm = new HashMap<>();
        alarm.put(ApplicationConstants.HOUR, String.valueOf(multipleHours[i]));
        alarm.put(ApplicationConstants.MINUTE, String.valueOf(multipleMinutes[i]));
        alarm.put(ApplicationConstants.REMINDER, String.valueOf(multipleReminders[i]));
        alarm.put(ApplicationConstants.DESTINATION, String.valueOf(multipleDestinations[i]));
alarmClocks.add(alarm);
}
Getting 'Type mismatch: cannot convert from ArrayList<HashMap<String,String>> to List<Map<String,Strin

Getting 'Type mismatch: cannot convert from ArrayList<HashMap<String,String>> to List<Map<String,Strin


By : user2377682
Date : March 29 2020, 07:55 AM
it helps some times Although ArrayList is a sub class of List, and Map is a subclass of HashMap, an List is NOT a subclass of List. Similarly you cannot cast a List to a List. If we could, it would mean we could add let's say a TreeMap to our List, and then cast it to a List, thus violating the original contract of the List.
Personally I would just use a diamond operator (Java 7+) if the recordMapList-instance is immediately created:
code :
List<Map<String, String>> recordMapList = new ArrayList<>();
List<Map<String, String>> recordMapList;
...
recordMapList = new ArrayList<Map<String, String>>();
How can I convert a HashMap<String, ArrayList<String>> to a HashMap<String, String[]>?

How can I convert a HashMap<String, ArrayList<String>> to a HashMap<String, String[]>?


By : Amanda Powell
Date : March 29 2020, 07:55 AM
help you fix your problem ArrayList has overloaded the toArray method.
The first form, toArray(), will return an Object[] back. This isn't what you want, since you can't convert an Object[] into a String[].
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