On Thu, Sep 16, 2010 at 12:59:08PM -0600, Vince Spicer wrote: > On Thu, Sep 16, 2010 at 12:49 PM, Vince Spicer <vi...@vinces.ca> wrote:
> > On Thu, Sep 16, 2010 at 12:27 PM, Michael Powe <mich...@trollope.org>wrote: > >> alist = ['label', 'guid'] > >> blist = ['column0label', 'column1label', 'dimension0guid', > >> 'description', 'columnid'] > >> > >> I want to iterate over blist and extract the items that match my > >> substrings in alist; alternatively, throw out the items that aren't in > >> alist (but, I've had bad experiences removing items from lists "in > >> place," so I tend toward the "copy" motif.) > > One solution is to use list comprehensions. > > newlist = [x for x in blist if [a for a in alist if a in x]] > > This works, although there may be more efficient ways to accomplish this > On major speed up is to make a simple filter that returns as soon as a match > is found instead of > completing the loop every element in alist > def filter_(x, against): > for a in against: > if a in x: > return True > return False > > newlist = [x for x in blist if filter_(x, alist)] Hello, Very cool, thanks. I've used list comprehensions before but I just couldn't get the structure right this time, for some reason. Thanks. mp -- Michael Powe mich...@trollope.org Naugatuck CT USA "No provision in our Constitution ought to be dearer to man than that which protects the rights of conscience against the enterprises of the civil authority." -- Thomas Jefferson to New London Methodists, 1809. ME 16:332
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