Comment #4 on issue 3533 by siguctua: add Dictionary>>at:ifAbsentValue: http://code.google.com/p/pharo/issues/detail?id=3533 Of course, you can always use: dict at: x ifAbsent: y except that it is not always desirable to send #value message to 'y' argument, especially if you can't tell anything about nature of objects you are storing in dictionary, and when speed is essential, it would be good to have something like this: at: key ifAbsentValue: defaultValue "Answer the value associated with the key or, if key isn't found, answer the default value" ^((array at: (self findElementOrNil: key)) ifNil: [ ^ defaultValue ]) value Cog VM shows a significant difference in delivering an answer: | dict | dict := Dictionary new. dict at: #a put: 1. [ 1000000 timesRepeat: [ dict at: #foo ifAbsentValue: #bar ] ] timeToRun 236 234 239 [ 1000000 timesRepeat: [ dict at: #a ifAbsentValue: #bar ] ] timeToRun 241 234 236 237 [ 1000000 timesRepeat: [ dict at: #foo ifAbsent: [#bar] ] ] timeToRun 322 318 [ 1000000 timesRepeat: [ dict at: #a ifAbsent: [ #bar ] ] ] timeToRun 363 336 340

On Wed, 12 Jan 2011, pharo@googlecode.com wrote:

Comment #4 on issue 3533 by siguctua: add Dictionary>>at:ifAbsentValue: http://code.google.com/p/pharo/issues/detail?id=3533

Of course, you can always use:

dict at: x ifAbsent: y

except that it is not always desirable to send #value message to 'y' argument, especially if you can't tell anything about nature of objects you are storing in dictionary, and when speed is essential, it would be good to have something like this:

at: key ifAbsentValue: defaultValue "Answer the value associated with the key or, if key isn't found, answer the default value" ^((array at: (self findElementOrNil: key)) ifNil: [ ^ defaultValue ]) value

Cog VM shows a significant difference in delivering an answer:

| dict | dict := Dictionary new. dict at: #a put: 1.

[ 1000000 timesRepeat: [ dict at: #foo ifAbsentValue: #bar ] ] timeToRun 236 234 239

[ 1000000 timesRepeat: [ dict at: #a ifAbsentValue: #bar ] ] timeToRun 241 234 236 237

[ 1000000 timesRepeat: [ dict at: #foo ifAbsent: [#bar] ] ] timeToRun 322 318

[ 1000000 timesRepeat: [ dict at: #a ifAbsent: [ #bar ] ] ] timeToRun 363 336 340

Note that the block creation causes the slowdown, so if you create a block and reuse that, then there should be no measureable difference in performance. Try this: | absentBlock | absentBlock := [ #bar ]. [ 1000000 timesRepeat: [ dict at: #a ifAbsent: absentBlock ] ] timeToRun Levente