Using an Iterator as suggested is the best way to avoid this problem. Calling lines.get(i) may then be O(i), and your whole loop be O(n²) although O(n) is doable. Because creating a String array is just like creating and using any other Java object array, these examples also work as more generic object array examples.
#JAVA FOR LOOP THROUGH STRING HOW TO#
Maybe more subtle: if lines is a List, is may not be indexed (e.g., lines is a LinkedList). In this tutorial, I’ll show how to declare, populate, and iterate through Java string arrays, including the newer for-loop syntax. (Note that size could be calculated once before the loop.) The optimization will probably be completely negligible (especially since you are performing costly I/O in the loop). Note that your if check may be quite cheap if you assume that calculating size is constant-time. Treating the first element separately is much easier. A good way to avoid the problem is to treat the first or last element of your list specifically before (or after) entering the loop. Secondly, when writing to a file with a BufferedWriter, it's important to use newLine() rather than writing a \n.Īs you noticed, the if is checked at each loop although you know that it will be invalidated only on the last loop. Firstly, it doesn't actually address the general coding practice.
Here's my unsatisfying solution: //Write contents to the fileīufferedWriter writer = new BufferedWriter(new FileWriter(file)) Īlso, for those saying I should just join all the Strings with \n, that's not an adequate solution. So I need to do this every time except the last one.ĭespite the fact that this is a specific problem, I'm actually looking for a better general coding practice to deal with scenarios like this, since it isn't the first and won't be the last time I have to deal with it. If I use a normal loop without any further checks, this will create a blank line at the very end of the file for no reason. The specific issue is this: I am writing to a file and want to output a new line after each line written.
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