Combining multiple string arrays into one

Question

Basically I have multiple string arrays and I want to combine them.

Not just extend the first array but combine a[0] and b[0] into single line.

like so:

String[] a = {"line1", "line2"};
String[] b = {"line3", "line4"};
String[] c; 
Combine code here
c[0] == "line1line3";
c[1] == "line2line4";

I'm using commons lang v3 if that's any help.

I can combine the 2 arrays with

c = (String[]) ArrayUtils.addAll(a, b);

But that's just makes c = "line1", "line2", "line3", "line4"

Anyone ever done this?

Answer 1

If the arrays have the same length, what about

for(int i = 0; i < a.length; ++i){
    c[i] = a[i] + b[i];
}

just concatenating corresponding strings in a loop?

Answer 2

You can use StringUtils.join from commons lang to "glue" the strings together:

for (int i = 0 ; i != c.length ; i++) {
    c[i] = StrungUtils.join(a[i], b[i]);
}

This might be a bit faster in case that you need to join more than two arrays, but in case of just two arrays it will almost certainly be slower.