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43 lines
1.6 KiB
R
43 lines
1.6 KiB
R
# Goal: Reading and writing ascii files, reading and writing binary files.
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# And, to measure how much faster it is working with binary files.
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# First manufacture a tall data frame:
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# FYI -- runif(10) yields 10 U(0,1) random numbers.
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B = data.frame(x1=runif(100000), x2=runif(100000), x3=runif(100000))
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summary(B)
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# Write out ascii file:
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write.table(B, file = "/tmp/foo.csv", sep = ",", col.names = NA)
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# Read in this resulting ascii file:
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C=read.table("/tmp/foo.csv", header = TRUE, sep = ",", row.names=1)
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# Write a binary file out of dataset C:
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save(C, file="/tmp/foo.binary")
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# Delete the dataset C:
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rm(C)
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# Restore from foo.binary:
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load("/tmp/foo.binary")
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summary(C) # should yield the same results
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# as summary(B) above.
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# Now we time all these operations --
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cat("Time creation of dataset:\n")
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system.time({
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B = data.frame(x1=runif(100000), x2=runif(100000), x3=runif(100000))
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})
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cat("Time writing an ascii file out of dataset B:\n")
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system.time(
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write.table(B, file = "/tmp/foo.csv", sep = ",", col.names = NA)
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)
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cat("Time reading an ascii file into dataset C:\n")
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system.time(
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{C=read.table("/tmp/foo.csv", header = TRUE, sep=",", row.names=1)
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})
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cat("Time writing a binary file out of dataset C:\n")
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system.time(save(C, file="/tmp/foo.binary"))
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cat("Time reading a binary file + variablenames from /tmp/foo.binary:\n")
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system.time(load("/tmp/foo.binary")) # and then read it in from binary file |