[Python] Suppressing newline writing to file after variable

Try line.rstrip() instead. It'll remove all newlines. Also, I suggest
you use string formatting, for example,

Thank you!

That works perfect, I'll have to look into string formatting more.

My next issue to solve I've been researching is:

How to condense a group of numbers to a wildcard list. For example:

252205
252206
252208
252220
252221
252222
252223
919745
919725
919785
704770 thru 704799 (all numbers listed individually in a file)

Condense to:
25220[568]
25222[0-3] (or 25222[0123] is fine too)
9197[248]5
7047[0-9][0-9]

Any recommendations on where to start, a method or function to research?

Thanks!

Edward Ellerbee



-----Original Message-----
From: Noah Hall [mailto:enalicho at gmail.com]
Sent: Tuesday, June 28, 2011 12:18 PM
To: Ellerbee, Edward
Cc: python-list at python.org
Subject: Re: Suppressing newline writing to file after variable

Hm, perhaps re (http://docs.python.org/library/re.html). It depends on
whether it's a standard static set of values you need to compare
against, or a undefined dynamic set.

Assuming you have the list sorted (if not, that's the first place to
start), I'd do a six-pass approach - one pass for each digit. It's
simple and readable, and I doubt you'll be working with enough numbers
for its inefficiency to be a problem. Something like this (untested
code):

lastprefix=tails=None
for cur in list_of_numbers:
prefix=cur[:5]; tail=cur[5]
if prefix!=lastprefix:
if lastprefix!=None:
if len(tails)>1: emit("%s[%s]"%(lastprefix,tails))
else emit(lastprefix+tails)
lastprefix,tails=prefix,""
tails+=tail
if lastprefix!=None:
if len(tails)>1: emit("%s[%s]"%(lastprefix,tails))
else emit(lastprefix+tails)

Feed the emitted results from this pass into the next pass, in which
prefix is cur[:4] and tail is cur[4], etc. For the subsequent passes,
you'll also need to worry about a suffix (which would be cur[5:] when
you're looking at cur[4]), and ensure that that matches, same as the
prefix.

This is completely untested, but it should be a start. (Replace the
calls to the imaginary "emit" function with whatever you do to emit
results - for the intermediate passes, that's probably appending to a
list.)

Chris Angelico

Typo in the above code. The else needs a colon after it, both times.

ChrisA

I'm responding on-list as I believe others will wish to weigh in (if
only to point out some improvements to my code - it's hastily put
together). Caution, post is long.

Defining functions in Python is, broadly speaking, just a matter of
collecting up a bunch of statements and giving it a name. Compare:

if x>5:
do_this()
do_that()
etc()

with:

def abcde():
do_this()
do_that()
etc()

The first one does the three statements, in order, if and only if the
condition is true. The second one gives a name to those three
statements, so you can use it as a new statement:

abcde()

It'll do the same three things, every time you call it. It's
effectively the same as putting the function's body in where you call
it (that's an extremely sloppy explanation, but near enough).
Yes, that would be the place to put it.

Here's a reworked version that you can test in IDLE:


def combine(list_of_numbers, position):
lastprefix=tails=lastsuffix=None
result=[]
for cur in list_of_numbers:
prefix=cur[:position]; tail=cur[position]; suffix=cur[position+1:]
if prefix!=lastprefix or suffix!=lastsuffix:
if lastprefix!=None:
if len(tails)>1: result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
lastprefix,tails,lastsuffix=prefix,"",suffix
tails+=tail
if lastprefix!=None:
if len(tails)>1: result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
return result

It incorporates some of the enhancements I mentioned in the original post.
['25220[568]']
['2522[012]5']

Notice that the 'emit' function is now 'result.append()' - it builds
up a list to return. You can now chain the calls; start with a list of
numbers and then call combine() in a loop.

# List of numbers from your previous post
numbers = ['252205', '252206', '252208', '252220', '252221', '252222',
'252223', '919745', '919725', '919785', '704770', '704771', '704772',
'704773', '704774', '704775', '704776', '704777', '704778', '704779',
'704780', '704781', '704782', '704783', '704784', '704785', '704786',
'704787', '704788', '704789', '704790', '704791', '704792', '704793',
'704794', '704795', '704796', '704797', '704798', '704799']


numbers = combine(numbers,5)

numbers = combine(numbers,4)

numbers = combine(numbers,3)

numbers = combine(numbers,2)

numbers = combine(numbers,1)

numbers = combine(numbers,0)

If you do these statements one at a time in IDLE and inspect the
'numbers' list each time, you'll see the combinations sorting
themselves out. (With this starting list, only the first two will have
any effect.)

The last set of calls can be turned into a for loop:
for pos in range(5,-1,-1):
numbers = combine(numbers,pos)

In fact, you could actually take it out of being a function, if you wanted to:

list_of_numbers = ['252205', '252206', '252208', '252220', '252221',
'252222', '252223', '919745', '919725', '919785', '704770', '704771',
'704772', '704773', '704774', '704775', '704776', '704777', '704778',
'704779', '704780', '704781', '704782', '704783', '704784', '704785',
'704786', '704787', '704788', '704789', '704790', '704791', '704792',
'704793', '704794', '704795', '704796', '704797', '704798', '704799']

for position in range(5,-1,-1):
lastprefix=tails=lastsuffix=None
result=[]
for cur in list_of_numbers:
prefix=cur[:position]; tail=cur[position]; suffix=cur[position+1:]
if prefix!=lastprefix or suffix!=lastsuffix:
if lastprefix!=None:
if len(tails)>1: result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
lastprefix,tails,lastsuffix=prefix,"",suffix
tails+=tail
if lastprefix!=None:
if len(tails)>1: result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
list_of_numbers = result

That's what the function definition does - it takes a block of code
and gives it a new name. (There's a lot more to it than that, thank
you pedants I know, but in this simple example that's what it's
doing.)

Hope that's of use!

Chris Angelico

Holy cow, that's perfect!

Thanks so much :)

Would it be alright if I post my code on the list for critiquing? I'm
learning python to supplement my voice engineering position - time
consuming tasks that can be automated will take less time.


Edward Ellerbee


-----Original Message-----
From: python-list-bounces+eellerbee=bbandt.com at python.org
[mailto:python-list-bounces+eellerbee=bbandt.com at python.org] On Behalf
Of Chris Angelico
Sent: Thursday, July 14, 2011 10:39 AM
To: python-list at python.org
Subject: Re: Suppressing newline writing to file after variable

On Fri, Jul 15, 2011 at 12:04 AM, Ellerbee, Edward
wrote:
I'm responding on-list as I believe others will wish to weigh in (if
only to point out some improvements to my code - it's hastily put
together). Caution, post is long.

Defining functions in Python is, broadly speaking, just a matter of
collecting up a bunch of statements and giving it a name. Compare:

if x>5:
do_this()
do_that()
etc()

with:

def abcde():
do_this()
do_that()
etc()

The first one does the three statements, in order, if and only if the
condition is true. The second one gives a name to those three
statements, so you can use it as a new statement:

abcde()

It'll do the same three things, every time you call it. It's effectively
the same as putting the function's body in where you call it (that's an
extremely sloppy explanation, but near enough).
Yes, that would be the place to put it.

Here's a reworked version that you can test in IDLE:


def combine(list_of_numbers, position):
lastprefix=tails=lastsuffix=None
result=[]
for cur in list_of_numbers:
prefix=cur[:position]; tail=cur[position]; suffix=cur[position+1:]
if prefix!=lastprefix or suffix!=lastsuffix:
if lastprefix!=None:
if len(tails)>1:
result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
lastprefix,tails,lastsuffix=prefix,"",suffix
tails+=tail
if lastprefix!=None:
if len(tails)>1:
result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
return result

It incorporates some of the enhancements I mentioned in the original
post.
['25220[568]']
['2522[012]5']

Notice that the 'emit' function is now 'result.append()' - it builds up
a list to return. You can now chain the calls; start with a list of
numbers and then call combine() in a loop.

# List of numbers from your previous post numbers = ['252205', '252206',
'252208', '252220', '252221', '252222', '252223', '919745', '919725',
'919785', '704770', '704771', '704772', '704773', '704774', '704775',
'704776', '704777', '704778', '704779', '704780', '704781', '704782',
'704783', '704784', '704785', '704786', '704787', '704788', '704789',
'704790', '704791', '704792', '704793', '704794', '704795', '704796',
'704797', '704798', '704799']


numbers = combine(numbers,5)

numbers = combine(numbers,4)

numbers = combine(numbers,3)

numbers = combine(numbers,2)

numbers = combine(numbers,1)

numbers = combine(numbers,0)

If you do these statements one at a time in IDLE and inspect the
'numbers' list each time, you'll see the combinations sorting themselves
out. (With this starting list, only the first two will have any effect.)

The last set of calls can be turned into a for loop:
for pos in range(5,-1,-1):
numbers = combine(numbers,pos)

In fact, you could actually take it out of being a function, if you
wanted to:

list_of_numbers = ['252205', '252206', '252208', '252220', '252221',
'252222', '252223', '919745', '919725', '919785', '704770', '704771',
'704772', '704773', '704774', '704775', '704776', '704777', '704778',
'704779', '704780', '704781', '704782', '704783', '704784', '704785',
'704786', '704787', '704788', '704789', '704790', '704791', '704792',
'704793', '704794', '704795', '704796', '704797', '704798', '704799']

for position in range(5,-1,-1):
lastprefix=tails=lastsuffix=None
result=[]
for cur in list_of_numbers:
prefix=cur[:position]; tail=cur[position]; suffix=cur[position+1:]
if prefix!=lastprefix or suffix!=lastsuffix:
if lastprefix!=None:
if len(tails)>1:
result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
lastprefix,tails,lastsuffix=prefix,"",suffix
tails+=tail
if lastprefix!=None:
if len(tails)>1:
result.append("%s[%s]%s"%(lastprefix,tails,lastsuffix))
else: result.append(lastprefix+tails+lastsuffix)
list_of_numbers = result

That's what the function definition does - it takes a block of code and
gives it a new name. (There's a lot more to it than that, thank you
pedants I know, but in this simple example that's what it's
doing.)

Hope that's of use!

Chris Angelico

If it's not too long, sure! If it's more than can conveniently be
read, post it on one of those code-sharing places like
http://pastebin.com/ and post a link; then those who want to read it
can do so, and those who would rather avoid it have that option too.

ChrisA