delete from pattern to pattern if it contains match

Fri Apr 22 05:24:06 EDT 2016

harirammanohar at gmail.com wrote:
> On Thursday, April 21, 2016 at 7:03:00 PM UTC+5:30, Jussi Piitulainen
> wrote:
>> harirammanohar at gmail.com writes:
>>>> > On Monday, April 18, 2016 at 12:38:03 PM UTC+5:30,
>> > hariram... at gmail.com wrote:
>> >> HI All,
>> >> 
>> >> can you help me out in doing below.
>> >> 
>> >> file:
>> >> <start>
>> >> guava
>> >> fruit
>> >> <end>
>> >> <start>
>> >> mango
>> >> fruit
>> >> <end>
>> >> <start>
>> >> orange
>> >> fruit
>> >> <end>
>> >> 
>> >> need to delete from start to end if it contains mango in a file...
>> >> 
>> >> output should be:
>> >> 
>> >> <start>
>> >> guava
>> >> fruit
>> >> <end>
>> >> <start>
>> >> orange
>> >> fruit
>> >> <end>
>> >> 
>> >> Thank you
>> >
>> > any one can guide me ? why xml tree parsing is not working if i have
>> > root.tag and root.attrib as mentioned in earlier post...
>>>> Assuming the real consists of lines between a start marker and end
>> marker, a winning plan is to collect a group of lines, deal with it, and
>> move on.
>>>> The following code implements something close to the plan. You need to
>> adapt it a bit to have your own source of lines and to restore the end
>> marker in the output and to account for your real use case and for
>> differences in taste and judgment. - The plan is as described above, but
>> there are many ways to implement it.
>>>> from io import StringIO
>>>> text = '''\
>> <start>
>> guava
>> fruit
>> <end>
>> <start>
>> mango
>> fruit
>> <end>
>> <start>
>> orange
>> fruit
>> <end>
>> '''
>>>> def records(source):
>> current = []
>> for line in source:
>> if line.startswith('<end>'):
>> yield current
>> current = []
>> else:
>> current.append(line)
>>>> def hasmango(record):
>> return any('mango' in it for it in record)
>>>> for record in records(StringIO(text)):
>> hasmango(record) or print(*record)
>> Hi,
>> not working....this is the output i am getting...
>> \

This means that the line
>> text = '''\

has trailing whitespace in your copy of the script.
> <start>
> guava
> fruit
>> <start>
> orange
> fruit

Jussi forgot to add the "<end>..." line to the group. To fix this change the 
generator to
def records(source):
 current = []
 for line in source:
 current.append(line)
 if line.startswith('<end>'):
 yield current
 current = []
>> hasmango(record) or print(*record)

The
print(*record)
inserts spaces between record entries (i. e. at the beginning of all lines 
except the first) and adds a trailing newline. You can avoid this by 
specifying the delimiters explicitly:
if not hasmango(record):
 print(*record, sep="", end="")
Even with these changes code still looks somewhat brittle...