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Wimbledon Neck

What use is the "+=" operator? Why did the language designers bother to provide it? Yet they did ...

In Perl and PHP

$number_on_bus = $number_on_bus + $goton_here;
becomes
$number_on_bus += $goton_here;

In Python

number_on_bus = number_on_bus + goton_here
becomes
number_on_bus += goton_here

In C and Java

number_on_bus = number_on_bus + goton_here;
becomes
number_on_bus += goton_here;

The += operator adds the result of evaluating the expression to the right into the variable named on the left.

The code is shorter, but there's more too it than that. It makes the code easier to maintain - it saves what we call "Wimbledon Neck" which is very appropriate for me to be writing about this week as the tennis championships are just about to start. If I write
$longvariablename = $longthingummyname + $some;
then anyone coming along to maintain the code has to take a careful look on both sides of the assignment to see whether or not the information is being saved in the same slot from which it was loaded or not; can you visualise the maintainer turning his neck to the left, to the right, to the left, to the right rather like watching a tennis volley from the side line? If the element being used is a member of an array (= list in Perl) or hash (= dictionary, = associative array) then that's all the more checking to do.

So - it may not come natural to you to code += (or -= *= /= etc) but please do so ... you're making life easier for those who follow behind!
(written 2005-06-20, updated 2006-06-05)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
C203 - C and C based languages - Conditionals and Loops
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  [4322] Learning to Program - the conditional statement (if) - (2014-11-21)
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  [3200] How a for loop works Java, Perl and other languages - (2011-03-12)
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  [3004] Increment operators for counting - Perl, PHP, C and others - (2010-10-18)
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H104 - PHP - Control Statements
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  [3895] Flowchart to program - learning to program with Well House - (2012-10-14)
  [2912] Predictions for the seagull population - (2010-08-09)
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  [421] Don't repeat code - use loops or functions - (2005-08-21)
  [406] Assignment, equality and identity in PHP - (2005-08-08)
  [340] Code and code maintainance efficiency - (2005-06-08)

J704 - Java - Loops and Conditional Statements
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  [2734] for and foreach in Java - (2010-04-22)

P204 - Perl - Conditionals and Loops
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  [788] New - Conditional expressions in Python 2.5 - (2006-07-01)
  [668] Python - block insets help with documentation - (2006-04-04)
  [299] What - no switch or case statement? - (2005-05-03)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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