[issue9240] different behaviour with for loop... interpreted vs scripted
Diego Jacobi
report at bugs.python.org
Tue Jul 13 02:11:13 CEST 2010
New submission from Diego Jacobi <jacobidiego at gmail.com>:
Hi.
I am not a python expert and i was trying to reduce this next code:
data = []
i = 0
for j in range(packetlen+1):
print i, self.channels_in[ channels[i] ]
data.append( self.channels_in[ channels[i] ].pop() )
i += 1
if i >= len(channels):
i=0
into something like this:
data = []
for j in range(packetlen+1), i in channels:
print j, i
data.append( self.channels_in[ i ].pop() )
which is much more readable and short.
But i didnt know if this sintax is really supported (also i didnt found examples on internet), so i just tried.
I runned the script and it didnt complains with errors, BUT i found that the behavior is not what i expected.
I expected j to take value of range() and i to take the values of channels until range() gets empty.
well, the actual behavior is that j takes the value of the complete range() as in
j = range(..)
and the for loop iterates as in
for i in channels:
ALSO i tested this un the python command line and it produces different behaviours:
the same sintax writen as:
for j in range(1,5), i in range(120,500,12):
print j, i
produces
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'i' is not defined
Thats all. I guess that if it produces different results, then there is an error happening here.
If there is a pythonic way to do this:
for j in range(packetlen+1), i in channels:
please tell me.
Cheers.
Diego
----------
messages: 110150
nosy: jacobidiego
priority: normal
severity: normal
status: open
title: different behaviour with for loop... interpreted vs scripted
type: behavior
versions: Python 2.6
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<http://bugs.python.org/issue9240>
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