Trying to split a List in Java but I'm dumbfounded in indexing confusion-CodePudding

I have a List that I need to split because it gets sent to Google translate via the API and it has a List element size limit of 1024.

Here's the code (including the debugging code I added to try and figure this out):

    int size   = MASTER_LINE_LIST.size();
    int third  = size / 3;
    int start1 = 0;
    int end1   = start1   third;
    int start2 = end1   1;
    int end2   = start2   third;
    int start3 = end2   1;
    int end3   = size - 1;

    String msg1 = "start1 = "     start1      "\n"  
                  "end1   = "     end1        "\n\n"  
                  "start2 = "     start2      "\n"  
                  "end2   = "     end2        "\n\n"  
                  "start3 = "     start3      "\n"  
                  "end3   = "     end3        "\n\n";

    List<String> lineListSub0 = MASTER_LINE_LIST.subList(start1, end1);
    List<String> lineListSub1 = MASTER_LINE_LIST.subList(start2, end2);
    List<String> lineListSub2 = MASTER_LINE_LIST.subList(start3, end3);

    int mllSize = MASTER_LINE_LIST.size();
    int ll0Size = lineListSub0.size();
    int ll1Size = lineListSub1.size();
    int ll2Size = lineListSub2.size();
    int llTotal = ll0Size   ll1Size   ll2Size;
    String msg2 =  "Master list size = "              mllSize   "\n\n"  
                     "sublist 1 size = "              ll0Size   "\n"  
                     "sublist 2 size = "              ll1Size   "\n"  
                     "sublist 3 size = "              ll2Size   "\n\n"  
                     "total size of sublists = "      llTotal;

    System.out.println(msg1);
    System.out.println(msg2);

Here is the output from this code:

start1 = 0
end1   = 949

start2 = 950
end2   = 1899

start3 = 1900
end3   = 2846


Master list size = 2847

sublist 1 size = 949
sublist 2 size = 949
sublist 3 size = 946

total size of sublists = 2844

As you can see, the original List has 2,847 elements, yet the sum of the sizes of the subLists adds up to 2,844 ... I somehow lost three elements and I can't seem to find them because when I look at my start and end indexes that I use for the splits, they appear to me to be a cumulative series of numbers from 0 to 2846, as the start index of the next sublist is the end index of the previous sub-list plus 1 ... it looks right to me but why is it not adding up? Each sub-list SHOULD contain exactly 949 elements ... yet that third one doesn't ... but if I expand the boundaries of the indexes, I'll either get repeating data, or I'll go out of bounds.

What am I missing?

CodePudding user response：

Keep in mind that subList() does not include the toIndex, which means that in the following subList() you need to start at the toIndex of the previous subList().

int size   = MASTER_LINE_LIST.size();
int third  = size / 3;
int start1 = 0;
int end1   = start1   third;
int start2 = end1;
int end2   = start2   third;
int start3 = end2;
int end3   = size - 1;