Here is a numerical implementation of standard (continuous) Fourier tranform in Python/Sage. You should be able to test it directly on this page.
In order to use it on this page, click "Evaluate" after the following code to define the method, and then click again "Evaluate" below after the second part of the code to run a test example. You can modify the definition of the function in this example in order to calculate the Fourier transform of other functions.
