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I store an ArrayList in a file as a String ( arrayList.toString()).
How do i convert it back into an ArrayList?
Overall, I just want to convert something like: [Eve, Anna, Tony, Steve] back to an ArrayList. Any ideas?
All you need is a java.lang.String's split() & java.util.Arrays asList():
String fruits = "Orange,Apple,Grape";
String[] array = fruits.split(",");
List<String> list = Arrays.asList(array);
//Code to check the content in the List (for your understanding only)
for(String s : list) {
System.out.println(s);
}
Prints below output:
Orange
Apple
Grape
Related
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I have List<BigInteger> sample1 = Lists.newArrayList(BIGINTEGER1, BIGINTEGER2,BIGINTEGER3);
I have to create new List sample2 with one more value BIGINTEGER4 along with sample1 list:
How can I do that?
You can create a new ArrayList, and pass the other list in the constructor - the contents from the other list will then be passed/copied into the new:
List<BigInteger> sample2 = new ArrayList<>(sample1);
sample2.add(BIGINTEGER4);
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How to write the following code in one line in the function argument (in Kotlin or Java)?
/* list: ArrayList<String>, map: Map<String, String> */
val newList = ArrayList<String>()
for (item in list) newList.add(map[item])
someFun(newList)
I expect something like this:
someFun(/* code */)
Here is for Kotlin:
someFun(list.mapNotNull { map[it] })
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I want to find the specific word in the text file and store that word in the array of list.
I do not how it can be achieved or approached.
A basic solution:
public ArrayList getWords(String searchWord, String listOfWords){
ArrayList<String> foundWords = new ArrayList<>();
if (listOfWords.contains(searchWord)){
foundWords.add(searchWord);
}
return foundWords;
}
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I'm using Java to implement the Apriori algorithm but one problem exists.
ArrayList<String> l1=new ArrayList<>();//L1
...
ArrayList<String[]> lk1=l1;//Lk-1
Then it warns that: cannot convert from ArrayList<String> to ArrayList<String[]>. How can I solve this problem?
They're different types. Ignore the collection and just look at the underlying type.
String str = "This is a string.";
String[] array = str;
These are two different types, unconvertable, so as T for the collection, the collections are then unconvertable. Very basic concept here.
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String items = "bookcupdoll";
I want to add a comma in items variable like below:
book,cup,doll
How should I make the string become an array?
If you are asking how to convert a string to an array...
There is a handy method called "split(String separator)"
If the string looks like : String items = "book,cup,doll";
you can use it like this
String[] array = items.split(",");
And you will end up with an array of size 3 with the 3 different elements.