CODEWITHSUNDEEP
javastring
jay doank
jay doank

Reputation: 91

How to remove last character string in java

I want to remove comma in last data.

example:

i have code:

StringBuilder temp = new StringBuilder();

for (int i=0; i<allLines.size(); i++){
     StringBuilder temp2 = new StringBuilder();

     String[] abc = line.split("\t");

     temp2.append("{");
     temp2.append("id: \""+abc[0]+"\",");
     temp2.append("name: \""+abc[1]+"\",");
     temp2.append("},");

     temp.append(temp2.toString()); 

}

System.out.println("result : "+temp.toString());

ihave code and result:

{id: "1", name: "Jhames"},{id: "2", name: "Richard"},

but i want result:

{id: "1", name: "Jhames"},{id: "2", name: "Richard"}

Upvotes: 3

Views: 2331

Answers (6)

David P&#233;rez Cabrera
David P&#233;rez Cabrera

Reputation: 5048

No Java 8 solution:

StringBuilder temp = new StringBuilder();
adder(temp, allLines.get(0));

for (int i=1; i<allLines.size(); i++){
     temp.append(",");
     adder(temp, allLines.get(i));
}
System.out.println("result : "+temp.toString());

private static void adder(StringBuilder temp,String line){
    String[] abc = line.split("\t");
    temp.append("{id: \"");
    temp.append(abc[0]);
    temp.append("\",");
    temp.append("name: \"");
    temp.append(abc[1]);
    temp.append("\"}");
}

Upvotes: 1

Pshemo
Pshemo

Reputation: 124225

First of all you don't need two StringBuilders, so instead of 

StringBuilder sb1 = ..
for(..){
    StringBuilder sb2 = ...
    //fill sb2
    sb1.append(sb2);
}

you should use

StringBuilder sb1 = ..
for(..){
    //add all you want to sb1
    sb1.append(..)
    sb1.append(..)
}

Next thing is that you don't ever want to do 

sb.appent("foo" + x + "bar");

because it is same as 

sb.append(new StringBuilder("foo").append(x).append("bar").toString())

which is very ineffective because:

  1. you are creating separate StringBuilder each time you do so
  2. this new StringBuilder needs to unnecessary call toString method which has to copy all characters to new String which will later be copied to builder, instead of calling append(StringBuilder) and copy its characters directly.

So instead of sb.appent("foo" + x + "bar"); always write

sb.appent("foo").append(x).append("bar");

Now lets go back to your main problem. Since your code doesn't have declaration of line variable I am assuming that by

String[] abc = line.split("\t");

you mean 

String[] abc = allLines.get(i).split("\t");

So your code can look like

StringBuilder temp = new StringBuilder();

for (int i = 0; i < allLines.size(); i++) {

    String[] abc = allLines.get(i).split("\t");

    temp.append("{id: \"").append(abc[0]).append("\", ");
    temp.append("name: \"").append(abc[1]).append("\"}");
    if (i < allLines.size() - 1)
        temp.append(", ");
}

System.out.println("result : " + temp.toString());

Upvotes: 2

Rob Audenaerde
Rob Audenaerde

Reputation: 20029

Just use the new java 8 StringJoiner! (And other nifty Java methods)

Example:

StringJoiner joiner = new StringJoiner(",");
joiner.add("foo");
joiner.add("bar");
joiner.add("baz");
String joined = joiner.toString(); // "foo,bar,baz"

It also supports streams in the form of Collectors.joining(",")

Full example:

public static void main(String[] args) {

    String input = "1\tJames\n2\tRichard";
    String output =  Arrays.stream(input.split("\n"))
                        .map( i -> String.format("{ id: \"%s\", name: \"%s\" }", i.split("\t")))
                        .collect(Collectors.joining(","));

    //prints: { id: "1", name: "James" },{ id: "2", name: "Richard" }       
    System.out.println(output);

}

Upvotes: 8

Tuxxy_Thang
Tuxxy_Thang

Reputation: 189

Alternatively add this after your for loop

    temp.setLength(temp.length() - 1);

which requires no constant index checking in your code

Upvotes: 3

2787184
2787184

Reputation: 3881

You can use deleteCharAt() method.

 StringBuilder s = new StringBuilder("{id: \"1\", name: \"Jhames\"},{id: \"2\", name: \"Richard\"},");
 System.out.println(s.deleteCharAt(s.lastIndexOf(",")));

Upvotes: 2

Eran
Eran

Reputation: 393821

You can avoid appending it in the first place :

for (int i=0; i<allLines.size(); i++){
     StringBuilder temp2 = new StringBuilder();

     String[] abc = line.split("\t");

     temp2.append("{");
     temp2.append("id: \""+abc[0]+"\",");
     temp2.append("name: \""+abc[1]+"\",");
     temp2.append("}");
     if (i<allLines.size()-1)
         temp2.append(",");
     temp.append(temp2.toString()); 

}

Upvotes: 4

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