I have a problem with ArrayList in Java. I writing module for get all files from directory. But, i don't know how to print ALL elements from Array in ONE message. I mean:
File1
File2
File3
File4
File5
etc...
Print message should print new object in new line. No new print.
So, i think you know what i mean. I really don't know how to good explain it. Hope you can help me :D
If you have any questions, please comments :)
Also sorry for my bad english knowledge. Just learning it right now
Thanks.
You can use ArrayList#forEach to print each element of the list on a separate line. See the below code in action here.
list.forEach(System.out::println);
To combine all the objects as one String, you can append them all to a StringBuilder, as long as the object overrides the toString method. See the below code in action here.
final StringBuilder sb = new StringBuilder();
list.forEach(el->sb.append(el + System.lineSeparator()));
final String result = sb.toString();
System.out.print(result);
For Lists of Strings, you can use the simpler String.join(delimiter, list).
final String result = String.join(System.lineSeparator(), list);
System.out.println(result);
You can use a for loop to cycle through all elements of the arrayList and print them
Just assemble the elements into an object to print out at the same time. You weren't too specific about data type or what you are exactly doing so take this as more of a theoretical answer.
ArrayList arrayOfWhatever;
WhateverObject combinedWhatever;
for(Whatever whatever : arrayOfWhatever){
//put or append or add or whatever your file type is.
combined.add(whatever);
}
System.out.println(combinedWhatever);
If truly a string, you want to use a String Builder
ArrayList<String> strings;
StringBuilder combined;
for(String element : strings){
combined.append(element)
}
System.out.println(combined.toString())
https://docs.oracle.com/javase/tutorial/java/data/buffers.html
Collectors.joiningYou may join all strings in the input list together with "\n" thus any element will be printed on its line by using Collectors.joining.
public void printList(List<String> input) {
if (null != input) {
System.out.println(input.stream().collect(Collectors.joining("\n")));
}
}
Example usage.
String output = printList(List.of("File1", "File2", "File3", "File4", "File5" ));
File1
File2
File3
File4
File5
