paseline(my favorite simple script): does something similar exist?

[RickMuller]

One of my all-time favorite scripts is parseline, which is printed
below

def parseline(line, format):
xlat = {'x':None,'s':s tr,'f':float,'d ':int,'i':int}
result = []
words = line.split()
for i in range(len(forma t)):
f = format[i]
trans = xlat.get(f,'Non e')
if trans: result.append(t rans(words[i]))
if len(result) == 0: return None
if len(result) == 1: return result[0]
return result

This takes a line of text, splits it, and then applies simple
formatting characters to return different python types. For example,
given the line

H 0.000 0.000 0.000

I can call parseline(line, 'sfff') and it will return the string 'H',
and three floats. If I wanted to omit the first, I could just call
parseline(line, 'xfff'). If I only wanted the first 0.000, I could call
parseline(line, 'xf'). Clearly I don't do all of my parsing this way,
but I find parseline useful in a surprising number of applications.

I'm posting this here because (1) I'm feeling smug at what a bright
little coder I am, and (2) (in a more realistic and humble frame of
mind) I realize that many many people have probably found solutions to
similar needs, and I'd imaging that many are better than the above. I
would love to hear how other people do similar things.

Rick

[RickMuller]

Amazing! There were lots of great suggestions to my original post, but
I this is my favorite.

Rick

Fredrik Lundh wrote:

RickMuller wrote:

I'm posting this here because (1) I'm feeling smug at what a bright
little coder I am

if you want to show off, and use a more pythonic interface, you can do
it with a lot fewer lines. here's one example:

def parseline(line, *types):
result = [c(x) for (x, c) in zip(line.split( ), types) if c] or [None]
return len(result) != 1 and result or result[0]

text = "H 0.000 0.000 0.000"

print parseline(text, str, float, float, float)
print parseline(text, None, float, float, float)
print parseline(text, None, float)

etc. and since you know how many items you'll get back from the
function, you might as well go for the one-liner version, and do
the unpacking on the way out:

def parseline(line, *types):
return [c(x) for (x, c) in zip(line.split( ), types) if c] or [None]

text = "H 0.000 0.000 0.000"

[tag, value] = parseline(text, str, float)
[value] = parseline(text, None, float)

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