Re: how to get string in sci. notation to a number?

*To*: mathgroup at smc.vnet.net*Subject*: [mg124096] Re: how to get string in sci. notation to a number?*From*: "Oleksandr Rasputinov" <oleksandr_rasputinov at hmamail.com>*Date*: Mon, 9 Jan 2012 03:14:00 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <jb2hum$5e0$1@smc.vnet.net> <op.v5phrszkqcgwdu@core2.lan>

On Tue, 29 Nov 2011 11:48:54 -0000, Oleksandr Rasputinov <oleksandr_rasputinov at hmamail.com> wrote: > On Tue, 29 Nov 2011 12:07:50 -0000, 1.156 <rob at piovere.com> wrote: > >> I've been able to get a text file with data into a list of strings >> of the following form: >> >> {{"4.998865e+000", "9.564453e-006"}, >> {"5.630450e+000", "9.194384e-006"}, >> {"6.113276e+000", "8.134170e-006"}} >> >> After many hours I've really gotten nowhere except that it's most >> likely done with ToExpression which works fine with simple decimal >> numbers in string form. Must I really split up the strings, suck out the >> exponents, and then multiply them out to be able to use these numbers in >> a ListPlot? >> Any hints would be appreciated. > > In place of "e", Mathematica uses "*^". When reading output from a > Python program into Mathematica for analysis, I have used StringReplace > to convert to valid Mathematica syntax followed by ToExpression; this > can be faster and more convenient than Import in certain cases. However, > if you are happy with your current approach and just want to finish the > job, you can use e.g.: > > lst = { > {"4.998865e+000", "9.564453e-006"}, > {"5.630450e+000", "9.194384e-006"}, > {"6.113276e+000", "8.134170e-006"} > } > > Map[Sequence@@ImportString[#, "List", "Numeric" -> True] &, lst, {2}] > > {{4.99887, 9.56445*10^-6}, > {5.63045, 9.19438*10^-6}, > {6.11328, 8.13417*10^-6}} Perhaps it is not worth reviving this old thread, but I noticed another way to perform this task which may be of interest given the relatively frequent requirement for importation of numbers in this format into Mathematica: Map[Internal`StringToDouble, lst, {2}] Internal`StringToDouble seems to work in Mathematica 7 and 8. It exists in version 5.2 but appears to do nothing. I didn't try version 6.