where the extra space comes from on the stdout

[alf]

Hi,

I can not find out where the extra space comes from. Run following:

import os,sys
while 1:
print 'Question [Y/[N]]?',
if sys.stdin.readline().strip() in ('Y','y'):
#do something
pass

$ python q.py
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?n
Question [Y/[N]]?
Question [Y/[N]]?
There is a space evrywhere just before Q

Any insight?

--
alfz1

[Steve Holden]

alf wrote:

Hi,

I can not find out where the extra space comes from. Run following:

import os,sys
while 1:
print 'Question [Y/[N]]?',
if sys.stdin.readline().strip() in ('Y','y'):
#do something
pass

$ python q.py
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?n
Question [Y/[N]]?
Question [Y/[N]]?
There is a space evrywhere just before Q

Any insight?

Yup. When you execute a print statement with a comma at the end it
doesn't output the space, it simply sets a flag reminding it that there
should be a space before the next item on the same line. If the next
character out is a newline then the space flag is reset, but in this
case the newline was provided by the input, so you get a space at the
start of the next output.

regards
Steve
--
Steve Holden [phone] [phone]
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Skype: holdenweb http://holdenweb.blogspot.com
Recent Ramblings http://del.icio.us/steve.holden

[Gabriel G]

At Saturday 30/9/2006 19:09, Steve Holden wrote:

while 1:
print 'Question [Y/[N]]?',
if sys.stdin.readline().strip() in ('Y','y'):
#do something
pass

$ python q.py
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y

Yup. When you execute a print statement with a comma at the end it
doesn't output the space, it simply sets a flag reminding it that there
should be a space before the next item on the same line. If the next
character out is a newline then the space flag is reset, but in this
case the newline was provided by the input, so you get a space at the
start of the next output.

You could try using
print '\rQuestion?',
Gabriel Genellina
Softlab SRL

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[Simon Percivall]

alf wrote:

Hi,

I can not find out where the extra space comes from. Run following:

import os,sys
while 1:
print 'Question [Y/[N]]?',
if sys.stdin.readline().strip() in ('Y','y'):
#do something
pass

$ python q.py
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?y
Question [Y/[N]]?n
Question [Y/[N]]?
Question [Y/[N]]?
There is a space evrywhere just before Q

Any insight?

You already got the answer, but as for the rest: It's really easier for
you if you use raw_input() for your question/input pair instead.

[alf]

Simon Percivall wrote:

>
You already got the answer, but as for the rest: It's really easier for
you if you use raw_input() for your question/input pair instead.

thx, this is what I was looking for, alf