CODEWITHSUNDEEP
javaarrays
Levon Tamrazov
Levon Tamrazov

Reputation: 556

Getting an array from string.split() java

so I have the following bit of code:

while((line = reader.readLine()) != null) {
    String[] row = line.split(",");
    this.table.add(row);

Where this.table was initiated using:

ArrayList table = new ArrayList();

Then when I tried to get the length a row in table like so:

for(int i=0; i<table.size(); ++i){
    for(int j=0; j<table.get(i).length; ++j) {
        //some code    
        }

It (underlines get(i).length; and gives me an error saying that it cannot find symbol. symbol: length location: class Object.

What's wrong? Does string.split() not return an array? If it does, why can I not use any of the array class methods / variables?

Thank you!

Upvotes: 0

Views: 250

Answers (4)

chrome
chrome

Reputation: 659

ArrayList table = new ArrayList();
//  change with:
ArrayList<String[]> table = new ArrayList();

Upvotes: 0

Bohemian
Bohemian

Reputation: 425033

You need to type your list:

List<String[]> table = new ArrayList<String[]>();

then the java compiler will know the String[] are stored in your list.

Upvotes: 0

ppeterka
ppeterka

Reputation: 20726

You should use the java generics 

List<String[]> table = new ArrayList<String[]>();

Then you would get String[] instances with the get(i) calls. Also note using the List interface to declare the table variable. Wheever possible, use the superinterface that suits your needs, and not the implementation class.

Also, starting from Java 1.5, you can use the much more intuitive for syntax (of course, this assumes that you use the generics recommended before):

for(String[] processedRow : table){
    for(String processedField : processedRow) {
        //some code    
    }
}

Upvotes: 0

Sean Patrick Floyd
Sean Patrick Floyd

Reputation: 298898

An ArrayList is not a List of Arrays, it's a list backed by an array.

But you can make it a List of arrays by using generics.

List<String[]> table = new ArrayList<String[]>();

Then your code should work.

Upvotes: 2

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