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POR zero or one based?
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  1. POR zero or one based?
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    copied!<p>We have the following code in R (already stripped to the bone for debugging)</p> <pre><code>tgtStart = 29593 for (i in tgtStart:tgtStart) { PricerData[i, 1] = 111 } print(PricerData[29592,1]) </code></pre> <p>PricerData being a matrix constructed well beyond 29593 and pre filled with NAs.</p> <p>The thing I do not understand is that PricerData[29592, 1] will be changed to 111, this code prints 111, not the NA we expected.</p> <p>Just to make it a bit more elaborate, the code I ended with today was:</p> <pre><code>tgtStart = 29593 for (i in tgtStart:tgtStart) { print(PricerData[i,1]) print(PricerData[i-1,1]) PricerData[i, 1] = 111 print(PricerData[i,1]) print(PricerData[i-1,1]) } print(PricerData[29592,1]) </code></pre> <p>It will print:</p> <pre><code>[1] NA [1] NA [1] 111 [1] NA [1] 111 </code></pre> <p>All as expected till the end, why oh why is the element before our start changed? And why not in the loop, only after the closing of the for-loop (Oh and if we change the 29593 to 29596, all works as expected, me not comprehend.).</p> <p>Also, I don't code R, normally I'm doing C++, I'm to understand that R is one-based on it's vectors, but please do not mind to cover the real basics. We use R version 2.4.1.5, x64</p> <p>EDIT: Okay, it's clear that I cut too much from our code, so for you the problem went away, here is the full function, for reference, I do not understand the output it gives above</p> <pre><code>LoadPricer &lt;- function(instrument, colo, simDate, sliceSize, startTime, endTime, pricerName, pricerSettings, returnEmptyMatrixIfFileNotFound = FALSE) { fileName &lt;- paste ( simulatorOutputBasePath, instrument, '\\', colo, '\\', format(simDate, '%Y%m%d'), '\\', sliceSize, '\\P#', pricerName, '#', pricerSettings, '.csv', sep='') firstSliceRequest = GetSlicesSinceMidnight(startTime, sliceSize) lastSliceRequest = GetSlicesSinceMidnight(endTime, sliceSize) PricerData = as.matrix(matrix(NA, nrow=(lastSliceRequest - firstSliceRequest + 1), ncol = 1)) if (file.exists(fileName)) { # Load entire file AllData = as.data.frame(read.csv(fileName, header = TRUE, colClasses=c("customTimeFormat","numeric"))) if (dim(AllData)[1] &gt; 0) { firstSliceData = GetSlicesSinceMidnight(as.POSIXlt(AllData[1,1]), sliceSize) lastSliceData = GetSlicesSinceMidnight(as.POSIXlt(AllData[nrow(AllData),1]), sliceSize) if ( firstSliceData &lt;= lastSliceRequest &amp; lastSliceData &gt;= firstSliceRequest ) { tgtStart = max(1, firstSliceData - firstSliceRequest + 1) tgtEnd = min(lastSliceRequest - firstSliceRequest + 1, lastSliceData - firstSliceRequest + 1) srcStart = max(1, firstSliceRequest - firstSliceData + 1) srcEnd = min(lastSliceData - firstSliceData + 1, srcStart + tgtEnd - tgtStart) #PricerData[as.integer(tgtStart):as.integer(tgtEnd),1] = AllData[as.integer(srcStart):as.integer(srcEnd),2] for (i in tgtStart:tgtStart) { PricerData[i, 1] = 111# as.matrix(AllData[srcStart+i-tgtStart , 2]) } } } } else { if (returnEmptyMatrixIfFileNotFound) PricerData = matrix(NA, nrow=0, ncol=2) print(paste('WARNING: Unable to load Pricer! File:', fileName)) } return (PricerData) } </code></pre>
 

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