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Data Science Import and Export Wolfram Language

Posted 7 years ago

I've been scouring the forums and I've found many ways to transform dates. However, I'm stuck trying to figure out how to import a set of dates in a format that I can use in a time series. I'm not sure why Mathematica won't automatically recognize the format as that is were it originally came from via an exported DataDrop TSV file. I'm able to import the dates, can remove the last part of the string, but when I try DateObject it does not work. Yet, entering a single value as noted below working. hwd = Import["hw.tsv", {"Data", All, 1}]; rep = StringReplace[Rest[hwd], " GMT +0" -> ""] // InputForm; DateObject[rep] Ultimately I want to be able to import the file and be able to do a TimeSeries with the Date and the temperature without the degrees and plot it as a DateListPlot. Attachments:

POSTED BY: Michael Madsen

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Posted 7 years ago

POSTED BY: Hans Michel

Posted 7 years ago

Hi Michael, Try this: hwd = Import["hw.tsv", {"Data", All, 1}, "HeaderLines" -> 1]; rep = StringReplace[hwd, " GMT +0" -> ""]; DateObject /@ rep

POSTED BY: Michael Madsen

Posted 7 years ago

To further answer your question, I think it would be easier to import everything, then do a bit of manipulation on the columns. I'm not sure why you want to remove the temperature units, I'd just convert these to a Quantity and preserve the unit value. This works fine with TimeSeries/DateListPlot: hwd = Import["hw.tsv", "Data", "HeaderLines" -> 1]; hwd = MapAt[DateObject[StringReplace[#, " GMT +0" -> ""]] &, hwd, {All, 1}]; hwd = MapAt[Quantity, hwd, {All, 2}]; ts = TimeSeries[hwd] DateListPlot[ts] If you really want to remove the units, change the third line to : hwd = MapAt[ToExpression[StringReplace[#, " " ~~ __ -> ""]] &, hwd, {All, 2}];

POSTED BY: Sean Cheren

Posted 7 years ago

I have five different data exports. I had a workbook that allowed me to compare the means, and do trend analysis and comparisons for different temperature sensors in my house. However, DataDrop dropped the Degrees F from a value in a couple of the datasets and I'm not able to run them as it see the 62 differently that the rest of the data. The same process that works for the hw file, does not work for the basement file. That is why I'm trying to find a way to import, but normalize on the value only and use the Dates to create a new dataset that is easier to use going forward. Does that help? Attachments:

POSTED BY: Michael Madsen

Posted 7 years ago

Some of the values are not strings, so StringReplace is complaining.. An easy fix would be changing the 3rd line to hwd = MapAt[ToExpression[StringReplace[ToString[#], " " ~~ __ -> ""]] &, hwd, {All, 2}];