Blocking readline() Call?

[Scott Brady Drummonds]

Hi, everyone,

I'm just figuring Python out but have become stalled with the following
snippit of code: For some reason, the program stalls after the "read line:
x" for the last line. The 'done reading cycle map' message is never
generated:

while 1:
line = file.readline()
if line == '':
continue
data = line.strip().split(':')
cycleMap[int(data[0])] = int(data[1])
i = i + 1
print ('read line %d' % i)
file.close()
print ('done reading cycle map')

I thought readline() was supposed to be non-blocking. Have I misunderstood
something?

Thanks,
Scott

 

[Jp Calderone]

Hi, everyone,

I'm just figuring Python out but have become stalled with the following
snippit of code: For some reason, the program stalls after the "read line:
x" for the last line. The 'done reading cycle map' message is never
generated:

while 1:
line = file.readline()
if line == '':
continue

I think you mean "break" here, not "continue".

data = line.strip().split(':')
cycleMap[int(data[0])] = int(data[1])
i = i + 1
print ('read line %d' % i)
file.close()
print ('done reading cycle map')

Another way to write this loop would be:

for line in file:
...

Jp

 

[Peter Hansen]

I'm just figuring Python out but have become stalled with the following
snippit of code: For some reason, the program stalls after the "read line:
x" for the last line. The 'done reading cycle map' message is never
generated:

while 1:
line = file.readline()
if line == '':
continue

Correct this: you want "break", not continue.

data = line.strip().split(':')
cycleMap[int(data[0])] = int(data[1])
i = i + 1
print ('read line %d' % i)
file.close()
print ('done reading cycle map')

I thought readline() was supposed to be non-blocking. Have I misunderstood
something?

Yes, the problem wasn't where you thought it was. A well-placed print
statement or two would have showed you that readline was being called
repeatedly, not blocking.

-Peter

 

[Scott Brady Drummonds]

Hi, everyone,

I'm just figuring Python out but have become stalled with the following
snippit of code:

[code deleted]

JP said:

I think you mean "break" here, not "continue".

Peter said:

Correct this: you want "break", not continue

Mel said:

'continue' doesn't mean what you think it means. Try 'break'.

So, what is it that you people are trying to tell me? Please don't beat
around the bush.

Scott

P.S. Sarcasm aside, thanks to all three of you for pointing out my very
basic mistake.

 

[Paul Clinch]

Hi, everyone,

I'm just figuring Python out but have become stalled with the following
snippit of code: For some reason, the program stalls after the "read line:
x" for the last line. The 'done reading cycle map' message is never
generated:

while 1:
line = file.readline()
if line == '':
continue

Perhaps you meant break.

data = line.strip().split(':')
cycleMap[int(data[0])] = int(data[1])
i = i + 1
print ('read line %d' % i)
file.close()
print ('done reading cycle map')

I thought readline() was supposed to be non-blocking. Have I misunderstood
something?

Thanks,
Scott

Regards, Paul Clinch

 

[Peter Hansen]

Hi, everyone,

I'm just figuring Python out but have become stalled with the following
snippit of code:

[code deleted]

JP said:

I think you mean "break" here, not "continue".

Peter said:

Correct this: you want "break", not continue

Mel said:

'continue' doesn't mean what you think it means. Try 'break'.

So, what is it that you people are trying to tell me? Please don't beat
around the bush.

Sorry we were unclear, Scott. See Paul Clinch's post for an answer that
is more concise and perhaps easier for you to understand. ;-) ;-)

-Peter