Re: [Tutor] iterating data and populating a dictionary
On Thu, Aug 7, 2008 at 12:42 AM, Shrutarshi Basu [EMAIL PROTECTED]wrote: If you're just going to be using numbers as dictionary keys, it might be simpler just to use a list structure. Dictionaries don't preserve order, so you'd need to write extra code if you ever need to iterate over it in order. It wouldn't be any (or at least much) more difficult than looping over a list of known/unknown length. Known length: for x in range(0, length): do something with mydict[x] Unknown length, dict keys starting at 0: for x in range(0, len(mydict)): do something with mydict[x] Known length, dict keys starting at 1: for x in range(1, (len(mydict)+1)): do something with mydict[x] Probably not the most elegant solution, but it does work. I can't really think of a particular reason it would be useful, though. The main reason a dict is useful is for key values that won't change, and aren't easily kept track of (i.e. names). It's a lot more difficult (at least for the interpreter, as in processor cycles) to find John Smith in a list, than to convert it to a hash value and look it up in a hash table. HTH, Wayne ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] iterating data and populating a dictionary
If you're just going to be using numbers as dictionary keys, it might be simpler just to use a list structure. Dictionaries don't preserve order, so you'd need to write extra code if you ever need to iterate over it in order. Since your code increments field everytime it gets a new record you can just use it as a list index and things should be fine. Of course you might have your own reasons for using a dict, so it's up to you. -- The ByteBaker : http://www.bytebaker.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] iterating data and populating a dictionary
i am filling a dictionary with a dictionary and my values for
isegment[field] are identical. i can't see where i am overwriting the
previous field values.
my data looks like
Field = aa1
Index = 0.0
Value = 0.0
...
...
Field = aa2
Index = 0.01
Value = 0.5
...
i would like to have something like, {1: {'Value': 0.0, ...}, 2: {'Value':
0.01, ...}}
for line in file(data_file):
the_line = line.split()
if the_line:
if the_line[0] == 'Field':
field += 1
elif the_line[0] == 'Index':
index = float(the_line[-1])
dif_index = index - start_index
iindex[field] = dif_index
start_index = index
elif the_line[0] == 'Value':
segment[the_line[1]] = float(the_line[-1])*(ax/40)
isegment[field] = segment
--
The game of science can accurately be described as a never-ending insult to
human intelligence. - João Magueijo
___
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Re: [Tutor] iterating data and populating a dictionary
maybe this can help
MainDictionary = {}
N = 0
for line in open('data_file', 'r'):
if line:
N += 1
a, b = line.split( = ) # = is in between spaces whish gives you
only two variables.
if a == 'Field':
MainDictionary[N] == {}
elif a == 'Index':
MainDictionary[N]['Value'] = {b}
2008/8/5 Bryan Fodness [EMAIL PROTECTED]
i am filling a dictionary with a dictionary and my values for
isegment[field] are identical. i can't see where i am overwriting the
previous field values.
my data looks like
Field = aa1
Index = 0.0
Value = 0.0
...
...
Field = aa2
Index = 0.01
Value = 0.5
...
i would like to have something like, {1: {'Value': 0.0, ...}, 2: {'Value':
0.01, ...}}
for line in file(data_file):
the_line = line.split()
if the_line:
if the_line[0] == 'Field':
field += 1
elif the_line[0] == 'Index':
index = float(the_line[-1])
dif_index = index - start_index
iindex[field] = dif_index
start_index = index
elif the_line[0] == 'Value':
segment[the_line[1]] = float(the_line[-1])*(ax/40)
isegment[field] = segment
--
The game of science can accurately be described as a never-ending insult
to human intelligence. - João Magueijo
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
___
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] iterating data and populating a dictionary
oops i forgot to count lines,
MainDictionary = {}
N = 0
M = 0
for line in open('data_file', 'r'):
if line:
if M 3:
N += 1
M += 1
a, b = line.split( = ) # = is in between spaces whish gives
you only two variables.
if a == 'Field':
MainDictionary[N] == {}
elif a == 'Index':
MainDictionary[N]['Value'] = {b}
else:
a, b = line.split( = ) # = is in between spaces whish gives
you only two variables.
if a == 'Field':
MainDictionary[N] == {}
elif a == 'Index':
MainDictionary[N]['Value'] = {b}
M = 0
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Re: [Tutor] iterating data and populating a dictionary
Bryan Fodness [EMAIL PROTECTED] wrote
i am filling a dictionary with a dictionary and my values for
isegment[field] are identical. i can't see where i am overwriting
the
previous field values.
Show us the full error text do not just summarize.
i would like to have something like, {1: {'Value': 0.0, ...}, 2:
{'Value':
Describe the output you expected and what you got (if anything)
for line in file(data_file):
the_line = line.split()
if the_line:
if the_line[0] == 'Field':
field += 1
elif the_line[0] == 'Index':
index = float(the_line[-1])
dif_index = index - start_index
iindex[field] = dif_index
Here index is assigned to a floating point number.
Then it is indexed. Floats don't have indexes...
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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Re: [Tutor] iterating data and populating a dictionary
Alan Gauld [EMAIL PROTECTED] wrote index = float(the_line[-1]) dif_index = index - start_index iindex[field] = dif_index Here index is assigned to a floating point number. Then it is indexed. Floats don't have indexes... Just noticed the indexed variable has a double i so not the same. Might be better to pick a more descriptive name though! :-) Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
