Is there such a thing as a moving bandpass filter algorithm? I am looking for an algorithm, preferably available in a Python library, which passes only frequencies of interest, with the center frequency continuously changing as it moves through an array of audio response data.

I need this because I am analyzing the result of an audio sine wave sweep from 20Hz to 20000Hz and the recorded data contains noise.  Since I am driving the system with a known frequency and am only interested in the system's response near that frequency, I would like to have a tracking bandpass filter.

I have Googled terms such as "moving bandpass filter" "tracking bandpass filter" to no avail. I would appreciate any suggestions.
Depends on what exactly you want to do but easiest would be Heterodyne detector: multiply with a local oscillator (cos() and sin()) with variable frequency followed by a lowpass with a fixed bandwidth. The cutoff frequency of the lowpass is equivalent to the bandwidth of the equivalent bandpass. The frequency of the local oscillator determines the center frequency. 

If you need non-uniform bandwidth (like 3rd octave for example), things get a little more complicated. You can do this primarily through frequency "warping". 

Finally, you can always table and/or interpolate filter coefficients.