[2.5.1] Building loop with some exceptions?

[Gilles Ganault]

Hello

I need to call a URL through a loop that starts at 01 and ends at 99,
but some of the steps must be ignored:

=====
url = "http://www.acme.com/list?code="
p = re.compile("^(\d+)\t(.+)$")

for i=01 to 99 except 04, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89:
f = urllib.urlopen(url + i)
page = f.read()
f.close()

for line in page:
m = p.search(line)
if m:
code = m.group(1)
label = m.group(2)

print "Code=" + code + " # Label=" + label
=====

I'm clueless at what the Python way is to do this :-/

Thank you for any help.

 

[Aaron Brady]

Hello

I need to call a URL through a loop that starts at 01 and ends at 99,
but some of the steps must be ignored:

=====
url = "http://www.acme.com/list?code="
p = re.compile("^(\d+)\t(.+)$")

for i=01 to 99 except 04, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89:

sorted( list( set( domain ) - set( exceptions ) ) )

Set subtraction.

 

[Gilles Ganault]

sorted( list( set( domain ) - set( exceptions ) ) )

Set subtraction.

Thanks a lot but... I don't know what the above means :-/

 

[Matimus]

Hello

I need to call a URL through a loop that starts at 01 and ends at 99,
but some of the steps must be ignored:

=====
url = "http://www.acme.com/list?code="
p = re.compile("^(\d+)\t(.+)$")

for i=01 to 99 except 04, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89:
        f = urllib.urlopen(url + i)
        page = f.read()
        f.close()

        for line in page:
                m = p.search(line)
                if m:
                        code = m.group(1)
                        label = m.group(2)

                        print "Code=" + code + " # Label=" + label
=====

I'm clueless at what the Python way is to do this :-/

Thank you for any help.

I would just do something like this (not tested):

url_tmpl = "http://www.acme.com/list?code=d"
p = re.compile("^(\d+)\t(.+)$")
EXCLUDED_VALUES = 4, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89

for i in xrange(1,100):
if i in EXCLUDED_VALUES:
continue
f = urllib.urlopen(url_tmpl % i)
try:
for line in f:
m = p.search(line)
if m:
code = m.group(1)
label = m.group(2)

print "Code=", code, "# Label=", label
finally:
f.close()

 

[bearophileHUGS]

Gilles Ganault:

Thanks a lot but... I don't know what the above means :-/

set(iterable) just builds a set, then you use the really usual set
semantics.

Anyway, maybe you may find this more easy to understand:

refused_indexes = set([4, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89])
for i in xrange(1, 100):
if i not in refused_indexes:
print i

Note: never put a zero before an integer number (because it will give
you troubles, defining octal numbers).

Bye,
bearophile

 

[Aaron Brady]

Thanks a lot but... I don't know what the above means :-/

This example produces the numbers 0..9, except 3, 5, and 9.

sorted( list( set( range( 10 ) ) - set( [ 3, 5, 9 ] ) ) )

[0, 1, 2, 4, 6, 7, 8]

 

[Gilles Ganault]

I would just do something like this (not tested):

Thanks a lot guys Worked first time.

I just have the usual issue with ASCII/Unicode:

=======
cursor.execute(sql)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xe9 in position
53: ordinal
not in range(128)
=======

Is there a way to get rid of this error once and for all?

Thank you.

 

[Steven D'Aprano]

Hello

I need to call a URL through a loop that starts at 01 and ends at 99,
but some of the steps must be ignored: ....
I'm clueless at what the Python way is to do this :-/

Perhaps you should start by doing the Python tutorial, so you'll be less
clueless of simple things like how to do a loop.

http://docs.python.org/tutorial/



for i in range(1, 100):
if i in (4, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89):
continue
do_rest_of_processing

 

[MRAB]

Thanks a lot but... I don't know what the above means :-/

This example produces the numbers 0..9, except 3, 5, and 9.

sorted( list( set( range( 10 ) ) - set( [ 3, 5, 9 ] ) ) )

[0, 1, 2, 4, 6, 7, 8]

FYI, 'set' accepts an iterable, so you don't need 'list':

sorted(set(range(10)) - set([3, 5, 9]))

[0, 1, 2, 4, 6, 7, 8]

 

[alex23]

I need to call a URL through a loop that starts at 01 and ends at 99,
but some of the steps must be ignored:

exclusions = [04, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89]
for i in (x for x in xrange(1,100) if x not in exclusions):
....

 

[Gilles Ganault]

for i in range(1, 100):
if i in (4, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89):
continue
do_rest_of_processing

Thanks for the sample.

 

[Gilles Ganault]

exclusions = [04, 34, 40, 44, 48, 54, 57, 67, 76, 83, 89]
for i in (x for x in xrange(1,100) if x not in exclusions):

Thanks guys.