Java has had a "traditional"
for loop from the beginning:
for (int k=0; k<Allwords.size(); k++) {
That's three semicolon separated elements:
• initial setting
• test to see if loop should continue
• action to be taken before each re-test
So that when that's used in a loop such as this:
for (int k=0; k
System.out.print(Allwords.get(k) );
System.out.println(" " +k);
}
you can handle each member of a collection (array, ArrayList, Vector, etc) in turn. But - if you don't actually need the position number (that's also known as the index - k in this example) - that's a considerable amount more syntax than you need.
From Java 1.5 (that's also know as Java 5), an alternative form of the
for loop has been available which is synonymous with the
foreach loop in languages such as PHP. Here's an example:
for (Object beads: Allwords) {
System.out.println(beads);
}
In effect, that's a shorthand notation. There's an iterator that passes the reference for each object in the collection in turn into the
beads variable, so that you can process each directly without the need to go via the variable k.
So the for-with-iterator is a great mechanism form processing each member of a collection where you're not concerned with the position number, nor the concept of "next" or "previous" records - but if position number is important, you'll want to stick with the traditional form or the loop.
(written 2010-04-22, updated 2010-04-23)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
J704 - Java - Loops and Conditional Statements [4427] Java example - for loop and conditionals from course exercise - (2015-02-16)
[4346] A behaviour driven example of writing a Java program - (2014-12-09)
[4323] Learning to program - Loop statements such as while - (2014-11-22)
[4322] Learning to Program - the conditional statement (if) - (2014-11-21)
[3397] Does a for loop evaluate its end condition once, or on every iteration? - (2011-08-18)
[3200] How a for loop works Java, Perl and other languages - (2011-03-12)
[3038] Setting up individual variables, and arrays, in Java - some commented examples - (2010-11-09)
[1696] Saying NOT in Perl, PHP, Python, Lua ... - (2008-07-04)
[1582] Ruby, C, Java and more - getting out of loops - (2008-03-19)
[1220] for loop - how it works (Perl, PHP, Java, C, etc) - (2007-06-06)
[353] Wimbledon Neck - (2005-06-20)
J714 - Java - Fundamental classes [4431] A Java servlet that is also a stand alone program. And a server that is also a web client. - (2015-02-19)
[4421] How healthy are the stars of stage and screen? - (2015-02-09)
[4396] Java Utility class - flexible replacement for array. Also cacheing in objects and multiple catch clauses example. - (2015-01-16)
[4330] Java - factory method, encapsulation, hashmap example - (2014-11-27)
[3048] String handling - from first steps to practical examples - (2010-11-13)
[2920] Sorting - naturally, or into a different order - (2010-08-14)
[2649] Length, size or capacity in Java? - (2010-02-24)
[2421] Sorting Collections of Objects in Java - (2009-09-25)
[2418] Viv.java uses unchecked or unsafe operations - explanation and cure - (2009-09-24)
[2323] Java Collection Objects in the java.util package - (2009-08-05)
[1910] Java - Generics - (2008-11-27)
[1502] Java, sorting, ArrayList example, generics - (2008-01-11)
[1062] Java sorting - comparable v comparator - (2007-02-02)
[42] Do languages change? - (2004-09-08)
Some other Articles
What is all this SESSION stuff about? (PHP)Improving your function calls (APIs) - General and PHPPerl Course FAQType checking, Java arrays and collectionsfor and foreach in JavaTravel Troubles and Jesus againAsking about JesusTraining Courses - time of changeBird Watching on the Melksham AvonUploading a document or image to its own URL via a browser