Converting '2.345e-17' strings into numbers while importing a CSV file?

[stef (Stefan Wolfrum)]

Hi all,

suppose we have a list of number pairs like this (first 11 lines of a .txt file):

0,3E-14
0.001,-7E-14
0.002,-4E-14
0.003,2.9E-13
0.004,3.1000000000000004E-13
0.005,1.2E-13
0.006,2.3E-13
0.007,-7E-14
0.008,1.1000000000000001E-13
0.0090000000000000011,1E-14
0.01,4E-14

Response:

{{"0,3E-14"}, {"0.001,-7E-14"}, {"0.002,-4E-14"}, {"0.003,2.9E-13"}, \
{"0.004,3.1000000000000004E-13"}, {"0.005,1.2E-13"}, \
{"0.006,2.3E-13"}, {"0.007,-7E-14"}, \
{"0.008,1.1000000000000001E-13"}, {"0.0090000000000000011,1E-14"}, \
{"0.01,4E-14"}, ... }

Now I imported this into a table:

values = Import["data.txt", "Table"]

And tried to plot it like this:

ListPlot[values]

Unfortunately, the result was only this:

Now I suspect that Mathematica (version 8, btw) didn’t understand the number format of the second number of the pairs (like “4E-14”).
Could that be the case? If so: how can these types of numbers be converted into “real” numbers Mathematica understands?

Or do we have another problem here?

Thanks so much!
Stefan.

[cormullion]

Try:

data = Import["data.txt", "CSV"] 

and then look at your input data using InputForm

data // InputForm

It looks better - no quotes:

{{0, 3.*^-14}, {0.001, -7.*^-14}, {0.002, -4.*^-14}, {0.003, 2.9*^-13}, 
 {0.004, 3.1000000000000004*^-13}, {0.005, 1.2*^-13}, {0.006, 2.3*^-13}, 
 {0.007, -7.*^-14}, {0.008, 1.1000000000000001*^-13}, 
 {0.009000000000000001, 1.*^-14}, {0.01, 4.*^-14}}

and plots OK too.

ListPlot[data, Joined -> True]

[stef (Stefan Wolfrum)]

Awesome! Thanks so much!