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Convert List to comma delimited string

Joe Gliniecki

Joined: Oct 25, 2007
Posts: 18
I'm converting some code to use some of the new features in Java 1.5. The old code looks something like this:

Is there a similar way to do this in a foreach loop? I can't find anything to check whether the current item in the foreach loop is the last one.

The only way I see to do it is either with the Iterator above, or with a foreach and getting rid of the comma at the end of the string after you exit the loop.

I know this isn't an earth shattering question, but curious if I'm missing another way to do this using foreach.

Jeanne Boyarsky
author & internet detective

Joined: May 26, 2003
Posts: 33102

I can think of two ways:
1) Use a boolean to check if you are in the first iteration of the loop.
2) Always add the delimiter and then do a substring at the end to get rid of the last one.

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Mike Simmons
Ranch Hand

Joined: Mar 05, 2008
Posts: 3028
I use something like this:

Rob Spoor

Joined: Oct 27, 2005
Posts: 20269

And Mike's code also included another good advice: use StringBuilder instead of String for all the adding.

Everytime you concatenate Strings using +, a new StringBuilder object will be created. For example, will be turned into By specifically using a StringBuilder, you'll make sure there is only one StringBuilder object instead of one per iteration.

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subject: Convert List to comma delimited string
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