CODEWITHSUNDEEP
java
maddy
maddy

Reputation: 149

Append to String at certain position

I have a String miscFlag which is of size 100. I need to append to this miscFlag starting from index 20 as 0-19 are reserved for some other info. And then append subsequently at certain positions only. Can we do this using StringBuilder/StringBuffer?

This is how i am trying to do it..

    StringBuilder info = new StringBuilder(miscFlag);
    info.append(" ");
    info.append(Misc.toTimestampLiteral(currentDate));//append this from pos 20
    info.append(" ");
    info.append(formattedStartTime);  //append this from pos 40

Here i am not able to specify the position from where to append.

Upvotes: 1

Views: 19088

Answers (4)

Chaitanya K
Chaitanya K

Reputation: 3

You can specify the sposition where you'd like to insert as below

StringBuilder info = new StringBuilder(miscFlag);
info.insert(19, Misc.toTimestampLiteral(currentDate) + " ");
info.insert(39, formattedStartTime + " ");

Upvotes: 0

user425367
user425367

Reputation:

Use the insert method.

info.insert(19, Misc.toTimestampLiteral(currentDate));

Upvotes: 3

Audrius Meškauskas
Audrius Meškauskas

Reputation: 21718

Fixed length fields are doable with StringBuilder but looks for me very clumsy and error-prone, I would not recommend. Use String.format, it is exactly for that you need - to create string where field widths and positions are important:

 String.format("A[%8s][%4s]", "ab","cd");

will result 

 A[      ab][  cd]

Upvotes: 0

Subhrajyoti Majumder
Subhrajyoti Majumder

Reputation: 41200

Use String#subString to cut 0 to 20 index and then add new String.

String str = miscFlag.substring(0,20)+ " "+Misc.toTimestampLiteral(currentDate)+" "+  miscFlag.substring(21);

Upvotes: 1

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