I can't find a way to properly read a csv file containing complex numbers in the following form:
-5.07248931892817e-05+2.50260543778902e-18i,-5.0723848172051e-05+2.870855441657444e-17i,...
Example file available here
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2 Answers
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SemanticImport will handle it. Specify the column types explicitly. Example with one column:
SemanticImportString[
"-5.07248931892817e-05+2.50260543778902e-18i
-5.0723848172051e-05+2.870855441657444e-17i",
{"ComplexNumber"}
]
This returns a Dataset which you can convert to a list using Normal.
Update: I can import your file without problems in M10.0.2 like this:
str = Import["~/Downloads/f2.csvNk.csv", "String"];
Normal@SemanticImportString[
StringReplace[str, "," -> "\n"], {"ComplexNumber"}]
It's good practice to create tables with few columns and many rows. In this case, use newline as a separator instead of commas. I achieve this with StringReplace.
answered Jun 15, 2016 at 11:20
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$\begingroup$ I'm obtaining
Expression -0.0000507249+2.50261*10^-18 I at position {1} should be of type TypeSystemAnyType. >>` $\endgroup$– jsetJun 15, 2016 at 11:39 -
$\begingroup$ @jset It's impossible to tell what is going wrong unless we have a dataset that triggers the problem. The code I posted works in M10.4 and M10.0. $\endgroup$– SzabolcsJun 15, 2016 at 11:50
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$\begingroup$ @jset Just to be sure: do you have 10.0.2? If not you really should upgrade to at least 10.0.2. $\endgroup$– SzabolcsJun 15, 2016 at 12:57
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$\begingroup$ I know, on my personal notebook I have it, but my institution doesn't have it. Thank you $\endgroup$– jsetJun 15, 2016 at 13:07
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There is another solution, different from the one posted by @Szabolcs. It deals with string replacing and then converting to expression:
readMatlabComplex[file_] :=ToExpression[
StringSplit[
StringReplace[
ReadList[file, "String"]
, {"e" -> "*10^", "i" -> "*I"}]
, ","]]
It is about 10 times faster.
ewith*^andiwithI, and thenImportStringit. $\endgroup$