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| [[Category:R tool]] | | [[Category:R tool]] |
| {{tool|moderator=Jouni|stub=Yes}} | | {{tool|moderator=Jouni|stub=Yes}} |
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| | :''The code related to this tool is now a part of [[Opasnet (R library)]]. |
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| ==Question== | | ==Question== |
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| toe|MJ|35000|1 toe = 1000 kgoe = 1000 kg * 35 MJ/kg = 35000 MJ | | toe|MJ|35000|1 toe = 1000 kgoe = 1000 kg * 35 MJ/kg = 35000 MJ |
| </t2b> | | </t2b> |
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| <rcode
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| include="page:Opasnet_(R_library)|name:answer"
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| >
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| ############# convert.units: a function that converts units from one to another, if possible.
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| # value = a numeric vector with values to be converted
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| # fromunit = a numeric vector with the current units
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| # tounit = a string for the new units to be used. Must be found from the To column from the table in [[Unit conversions]].
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| # expo = exponent for the conversion. If -1 converts the inverse, i.e. backward, or a unit that is in the denominator of a compiled unit.
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| convert.units <- function(value, fromunit = NULL, tounit = NULL, expo = 1) {
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| data <- fetch("Op_en5475")
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| print(data)
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| out <- merge(fromunit, data, by.y = "From")
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| print(out)
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| out <- out[out$To == tounit, ]
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| print(out)
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| out <- merge(value, out, all.x = TRUE)
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| print(out)
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| out <- out$value * out$Factor^expo
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| print(out)
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| return(out)
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| }
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| cat("Starting model\n")
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| a <- data.frame(Unit = "MW", Result = 1)
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| convert.units(1, "MWh", "MJ")
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| temp <- setGeneric("convert.units")
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| temp <- setMethod(
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| f = "convert.units",
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| signature = signature(data = "ovariable"),
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| definition = function(x, tounit = NULL)
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| {
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| x@sample[c("Unit", "Result")] <- convert.units(x@sample$Result, x@sample$Unit, tounit)
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| return(x)
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| }
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| )
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| </rcode>
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| {{attack|# |The code does not work because the merges and combinations do not match. Values should have some row identifier that makes it possible to link a row in value to the right row in out. Should value and fromunit be two columns in a data.frame?|--[[User:Jouni|Jouni]] 11:29, 25 January 2012 (EET)}}
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Revision as of 13:48, 31 May 2012
- The code related to this tool is now a part of Opasnet (R library).
Question
How to convert data from one unit to another in R?
Answer
We need conversion factors, which are listed below, and a code that does the actual conversion.