VYAS ASHISH M-NTB837 wrote:
> > How about using list.index() and storing month names in a list? You may > want to measure performance your self and conclude. > > Regards, > Ashish Vyas > > -----Original Message----- > From: python-list-bounces+ntb837=motorola....@python.org > [mailto:python-list-bounces+ntb837=motorola....@python.org] On Behalf Of > wiso > Sent: Wednesday, January 06, 2010 4:34 PM > To: python-list@python.org > Subject: Convert month name to month number faster > > I'm optimizing the inner most loop of my script. I need to convert month > name to month number. I'm using python 2.6 on linux x64. > > > month_dict = {"Jan":1,"Feb":2,"Mar":3,"Apr":4, "May":5, "Jun":6, > "Jul":7,"Aug":8,"Sep":9,"Oct":10,"Nov":11,"Dec":12} > > def to_dict(name): > return month_dict[name] > > def to_if(name): > if name == "Jan": return 1 > elif name == "Feb": return 2 > elif name == "Mar": return 3 > elif name == "Apr": return 4 > elif name == "May": return 5 > elif name == "Jun": return 6 > elif name == "Jul": return 7 > elif name == "Aug": return 8 > elif name == "Sep": return 9 > elif name == "Oct": return 10 > elif name == "Nov": return 11 > elif name == "Dec": return 12 > else: raise ValueError > > import random > l = [random.choice(month_dict.keys()) for _ in range(1000000)] > > from time import time > t = time(); xxx=map(to_dict,l); print time() - t # 0.5 > t = time(); xxx=map(to_if,l); print time() - t # 1.0 > > > is there a faster solution? Maybe something with str.translate? > > The problem is a little different because I don't read random data, but > sorted data. For example: > > l = [x for x in > ("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec" > ) > for _ in range(1000)] # ["Jan","Jan", ..., "Feb", "Feb", ...] > > so maybe the to_if approach will be faster if I write the case in the > best > order. Look: > > l = ["Jan"] * 1000000 # to_if is in the best order for "Jan" > t = time(); xxx=map(to_dict,l); print time() - t # 0.5 > t = time(); xxx=map(to_if,l); print time() - t # 0.5 > > what just using get(key[, default])ΒΆ Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError. -- http://mail.python.org/mailman/listinfo/python-list
