Python iterators are objects (or functions, using some magic) thatrepeatedly produce values, one at a time, until they getexhausted. Python introduced this general feature to efficientlysupport things like:

for line in fp.readlines():    ... do something with each line ...

Without iterators, .readlines() would have to read the entire fileinto memory, split it up into lines, and return a huge list; now, thiscode only has one line in memory at any given

AJAX is short for 'Asynchronous Javascript And XML', the common termfor the technology behind highly interactive web sites like GoogleMaps and Google Mail. Given that the features AJAX enables (from thelarge to the small) are very appealing to designers, we're pretty muchguaranteed to see more and more use of it on web sites.

But please don't reach for AJAX too fast, because there is such athing as being too interactive.

AJAX's interactivity comes through communication, and communicationtakes