I want to run multiple transient simulations through a loop, and in each of those simulations I am trying to measure a certain "time difference", I want to collect all of these "time differences" in array(vector) maybe, so that I can check their mean, standard deviation,minimum and maxima when I am done with all of the simulations. Is there a way to do this in ngspice.

Yes you can do that. You can use the 'meas(ure)'command to measure a time difference and build a vector from these measurements. For the meas command syntax see the ngspice user manual, for the ngspice control language (how to build a vector etc) see this: https://ngspice.sourceforge.io/ngspice-control-language-tutorial.html