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Python solve problem with string operation

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  Python solve problem with string operation Nac Temha <naccttemha@gmail.com> - 2014-01-17 00:24 +0200
    Re: Python solve problem with string operation John Gordon <gordon@panix.com> - 2014-01-16 22:30 +0000
      Re: Python solve problem with string operation Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-16 22:48 +0000
        Re: Python solve problem with string operation John Gordon <gordon@panix.com> - 2014-01-16 22:58 +0000
    Re: Python solve problem with string operation giacomo boffi <pecore@pascolo.net> - 2014-01-17 01:17 +0100
      Re: Python solve problem with string operation giacomo boffi <pecore@pascolo.net> - 2014-01-17 01:38 +0100
    Re: Python solve problem with string operation Denis McMahon <denismfmcmahon@gmail.com> - 2014-01-17 00:30 +0000
    Re: Python solve problem with string operation "Rhodri James" <rhodri@wildebst.org.uk> - 2014-01-17 01:05 +0000
    Re: Python solve problem with string operation Asaf Las <roegltd@gmail.com> - 2014-01-16 17:36 -0800

#64109 — Python solve problem with string operation

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Hi everyone,

I want to do operation with chars in the given string. Actually I want to
grouping the same chars.

For example;

input : "344111133311222223377"
operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
output: "34131237"



How can I do without list, regular expression. just using string
operations. Using an effective methods of python for this problem.


Thanks,
Best regards.

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#64110

In <mailman.5607.1389911083.18130.python-list@python.org> Nac Temha <naccttemha@gmail.com> writes:

> --047d7b6d95d0367a3d04f01de490
> Content-Type: text/plain; charset=ISO-8859-1

> Hi everyone,

> I want to do operation with chars in the given string. Actually I want to
> grouping the same chars.

> For example;

> input : "344111133311222223377"
> operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
> output: "34131237"

input = "344111133311222223377"
output = []
previous_ch = None
for ch in input:
    if ch != previous_ch:
        output.append(ch)
        previous_ch = ch
print ''.join(output)

-- 
John Gordon         Imagine what it must be like for a real medical doctor to
gordon@panix.com    watch 'House', or a real serial killer to watch 'Dexter'.

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#64112

On 16/01/2014 22:30, John Gordon wrote:
> In <mailman.5607.1389911083.18130.python-list@python.org> Nac Temha <naccttemha@gmail.com> writes:
>
>> --047d7b6d95d0367a3d04f01de490
>> Content-Type: text/plain; charset=ISO-8859-1
>
>> Hi everyone,
>
>> I want to do operation with chars in the given string. Actually I want to
>> grouping the same chars.
>
>> For example;
>
>> input : "344111133311222223377"
>> operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
>> output: "34131237"
>
> input = "344111133311222223377"
> output = []
> previous_ch = None
> for ch in input:
>      if ch != previous_ch:
>          output.append(ch)
>          previous_ch = ch
> print ''.join(output)
>

Cheat, you've used a list :)

-- 
My fellow Pythonistas, ask not what our language can do for you, ask 
what you can do for our language.

Mark Lawrence

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#64113

In <mailman.5609.1389912537.18130.python-list@python.org> Mark Lawrence <breamoreboy@yahoo.co.uk> writes:

> > input = "344111133311222223377"
> > output = []
> > previous_ch = None
> > for ch in input:
> >      if ch != previous_ch:
> >          output.append(ch)
> >          previous_ch = ch
> > print ''.join(output)
> >

> Cheat, you've used a list :)

Ack!  I missed that the OP doesn't want to use lists.

Well, let's try this instead:

    import sys

    input = "344111133311222223377"
    previous_ch = None
    for ch in input:
         if ch != previous_ch:
             sys.stdout.write(ch)
             previous_ch = ch
    sys.stdout.write('\n')

-- 
John Gordon         Imagine what it must be like for a real medical doctor to
gordon@panix.com    watch 'House', or a real serial killer to watch 'Dexter'.

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#64117

Nac Temha <naccttemha@gmail.com> writes:

> Hi everyone,
>
> I want to do operation with chars in the given string. Actually I want to
> grouping the same chars.
>
> For example;
>
> input : "344111133311222223377"
> operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
> output: "34131237"
>
>
>
> How can I do without list, regular expression. just using string operations. 
> Using an effective methods of python for this problem.


% cat a.py
def f(s,n):
    if s[n+1] == s[n]:
        return s[:n]+s[n+1:], n
    return s, n+1

i = "344111133311222223377"
n = 0

while n+1 != len(i):
    i, n = f(i, n)

print i
% python a.py
34131237
% 

-- 
your instructor is a mean person

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#64119

giacomo boffi <pecore@pascolo.net> writes:

> % python a.py
> 34131237

% cat a.py 
i="344111133311222223377";n=0
while n+1!=len(i):i,n=(i[:n]+i[n+1:],n) if i[n+1]==i[n] else (i,n+1)
print i
% python a.py 
34131237
%
-- 
for Nikos

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#64118

On Fri, 17 Jan 2014 00:24:40 +0200, Nac Temha wrote:

> Hi everyone,
> 
> I want to do operation with chars in the given string. Actually I want
> to grouping the same chars.
> 
> For example;
> 
> input : "344111133311222223377"
> operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
> output: "34131237"

> How can I do without list, regular expression. just using string
> operations. Using an effective methods of python for this problem.

You can do it on one line, but it looks really messy:

output = ''.join([{x:input[x]for x in range(len(input))}[x]for x in range
(len({x:input[x]for x in range(len(input))}))if(x==0 or {x:input[x]for x 
in range(len(input))}[x-1]!={x:input[x]for x in range(len(input))}[x])])

It looks much better if you do it in steps:

a = {x:input[x]for x in range(len(input))}
b = [a[n]for n in range(len(a))if(n==0 or a[n-1]!=a[n])])
output = ''.join(b)

If you really want to do it using just 'string' ops:

for i in range(len(input)):
    if (i==0):
        output=input[0]
    elif input[i]!=input[i-1]:
        output+=input[i]

-- 
Denis McMahon, denismfmcmahon@gmail.com

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#64124

On Thu, 16 Jan 2014 22:24:40 -0000, Nac Temha <naccttemha@gmail.com> wrote:

> Hi everyone,
>
> I want to do operation with chars in the given string. Actually I want to
> grouping the same chars.
>
> For example;
>
> input : "344111133311222223377"
> operation-> (3)(44)(1111)(333)(11)(22222)(33)(77)
> output: "34131237"
>
>
>
> How can I do without list, regular expression. just using string
> operations. Using an effective methods of python for this problem.

I almost convinced myself this was homework, you know.  A hint as to why  
you might want such a thing would look a lot less suspicious :-)

The simplest way to do this is probably using groupby:


 from itertools import groupby

input = "344111133311222223377"
output = "".join(k for k, _ in groupby(s))
print output



-- 
Rhodri James *-* Wildebeest Herder to the Masses

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#64130

inpu = "344111133311222223377"
tstr = inpu[0]
for k in range(1, len(inpu)):
    if inpu[k] != inpu[k-1] :
        tstr = tstr + inpu[k] 

print(tstr)

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