java - 按长度拆分字符串，保持子字符串完整

Question

I've split the string "this is a test for thestring longer than" into substrings of length 7 (or less), so i have a List strList that looks like: [this, is, a, test, for, thestri, ng, longer, than]

i need to print this out in rows of length of 7, keeping substrings whole: [this is, a test, for, thestri, ng, longer, than]

but im getting this instead and i cant find the bug [this, this is, a test, for for, thestri, longer, ng than, seven, charact, ers]

so what i'm trying to do is get the length of the substring and compare it to the limit of 7 characters (L1) and if it less than L1 - take next substring and add it to the same row (providing sum of their lengths + whitespace between them is still 7 or less). new strings then added to List strList2

package mylessons;
import java.util.*;

public class Level160 {

    public static void main(String[] args) {
         int L1 = 7; // length limit
         int len1 = 0;
         String tmpStr1 = "";
         List<String> strList = new ArrayList<>();
         List<String> strList2 = new ArrayList<>();

         strList.add("this");
         strList.add("is");
         strList.add("a");
         strList.add("test");
         strList.add("for");
         strList.add("thestri");
         strList.add("ng");
         strList.add("longer");
         strList.add("than");
         System.out.println(strList);

         for (int k = 0; k < strList.size(); k++ ) {

                // substring is shorter than L1 - 1 -->> adding to tmpStr1
                if (strList.get(k).length() + len1 < L1 - 1) {
                    tmpStr1 = tmpStr1 + strList.get(k).toString() + " ";
                    len1 = (len1 + strList.get(k).length() + 1);
                }

                // substring is L - 1 (whitespace is last char) -->> adding to tmpStr -->> adding to strList2
                if (strList.get(k).length() + len1 == L1 - 1) {
                    tmpStr1 = tmpStr1 + strList.get(k).toString();
                    strList2.add(tmpStr1);
                    len1 = 0;
                    tmpStr1 = "";
                }

                // substring is L -->> adding to tmpStr -->> adding to strList2
                if (strList.get(k).length() + len1 == L1) {
                    tmpStr1 = tmpStr1 + strList.get(k).toString();
                    strList2.add(tmpStr1);
                    len1 = 0;
                    tmpStr1 = "";
                }

                if (strList.get(k).length() + len1 > L1) {
                    strList2.add(strList.get(k));
                }
            }
            System.out.println(strList2);
    }
}

any help appreciated:)

Answer 1

In the first iteration you run into the first if clause and into the second. But the second if clause doesn't clear tmpStr1. That might not be the only problem with your code but it hints to two things you should try to do when fixing your code in my opinion:

• Make sure you run into exactly one if clause every iteration.
• Clear tmpStr1 and len1 every time you add something to strList2.

Answer 2

ok, so i've made some adjustments, so it's a working piece of code you can use:) also i've added check for last substring in given string being shorter than given length limit.

List before: [this, is, a, test, for, thestri, ng, longer, than] List after: [this is, a test, for, thestri, ng, longer, than]

public static void main(String[] args) {
     int L1 = 7; // length limit
     int len1 = 0;
     String tmpStr1 = "";
     List<String> strList = new ArrayList<>();
     List<String> strList2 = new ArrayList<>();

     strList.add("this");
     strList.add("is");
     strList.add("a");
     strList.add("test");
     strList.add("for");
     strList.add("thestri");
     strList.add("ng");
     strList.add("longer");
     strList.add("than");
     System.out.println(strList);

     for (int k = 0; k < strList.size(); k++ ) {

            // last substring is shorter than L1
            if (strList.get(k).length() + len1 < L1 - 1 && k == strList.size() - 1) {
                strList2.add(strList.get(k));
                continue;
            }

            // substring is shorter than L1 -->> adding to tmpStr1
            if (strList.get(k).length() + len1 < L1 - 1) {
                tmpStr1 = tmpStr1 + strList.get(k).toString() + " ";
                len1 = (len1 + strList.get(k).length() + 1);
                continue;
            }

            // substring is L - 1 (whitespace is last char) -->> adding to tmpStr -->> adding to strList2
            if (strList.get(k).length() + len1 == L1 - 1) {
                tmpStr1 = tmpStr1 + strList.get(k).toString();
                strList2.add(tmpStr1.trim());
                len1 = 0;
                tmpStr1 = "";
            }

            // substring is L -->> adding to tmpStr -->> adding to strList2
            if (strList.get(k).length() + len1 == L1) {
                tmpStr1 = tmpStr1 + strList.get(k).toString();
                strList2.add(tmpStr1.trim());
                len1 = 0;
                tmpStr1 = "";
            }

            if (strList.get(k).length() + len1 > L1) {
                strList2.add(tmpStr1.trim());
                strList2.add(strList.get(k));
                len1 = 0;
                tmpStr1 = "";
            }

        }
        System.out.println(strList2);
}