I think "<-" is better than "=" in some cases.
======= 2005-12-07 08:51:30 Write：=======
>
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>======= 2005-12-07 04:17:03 您在来信中写道：=======
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>>From: [EMAIL PROTECTED]
>>>
>>> ronggui a �crit :
>>>
>>> > I think it is NOT just for historical reason.
>>> > see the following example:
>>> >
>>> >>rm(x)
>>> >>mean(x=1:10)
>>> > [1] 5.5
>>> >>x
>>> > Error: object "x" not found
>>>
>>> x is an argument local to mean(),
>>> did you expect another answer ?
>>>
>>> >>mean(x<-1:10)
>>> > [1] 5.5
>>> >>x
>>> > [1] 1 2 3 4 5 6 7 8 9 10
>>>
>>> What is the goal of this "example" ?
>>
>>I believe it's to show why "<-" is to be preferred over "=" for
>>assignment...
>
>Yeah,I want to show "<-" is to be preferred.
>Sorry for not making it clearly.
>
>>> Here with "<-",
>>> (voluntary, or not, side effect)
>>> the global variable x is, also, created.
>>> Did the writer really want that ???
>>
>>Very much so, I believe.
>>
>>> I though there were other specific statements
>>> especially intended for global assignment, eg "<<-".
>>
>>You need to distinguish assignment in function _call_ and assignment in
>>function _definition_. They ain't the same.
>>
>>> If this example was intended to prove "<-"
>>> is better than "="
>>> ... I'm not really convinced !
>>
>>In that case, let's try another one (which is one big reason I stopped using
>>"=" for assignment):
>>
>>
>>> long.comp <- function(n) {
>>+ Sys.sleep(n)
>>+ n
>>+ }
>>> result = long.comp(30)
>>> system.time(result = long.comp(30))
>>Error in system.time(result = long.comp(30)) :
>> unused argument(s) (result ...)
>>> system.time(result <- long.comp(30))
>>[1] 0.00 0.00 30.05 NA NA
>>> str(result)
>> num 30
>>
>>Cheers,
>>Andy
>>
>>>
>>
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>2005-12-07
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>Deparment of Sociology
>Fudan University
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GuangXing
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2005-12-07
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