Help with calcuations using imported numbers. 
July 6th, 2009, 07:56 PM
| | Newbie | | Join Date: Jul 2009
Posts: 22
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I have imported two columns of numbers from excel and now i need to use those two columns of numbers to calculate the following...
Average_Error = sum(map(lambda a, b: abs(a - b), My_High, Actual_High))/delta.days
I need the first column to be inserted where I have My_High in the code above, and I need the second column to be inserted where I have Actual_High in the code above. I used the following code to import the numbers... -
f = open("C:\users\cory\desktop\Verification.csv")
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dd = {}
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keys = f.readline().strip().split(',')
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for key in keys:
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dd.setdefault(key, [])
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for line in f:
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for i, item in enumerate(line.strip().split(',')):
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dd[keys[i]].append(int(item))
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f.close()
I don't know where to begin.
Thanks!
Last edited by bvdet; July 6th, 2009 at 08:47 PM.
Reason: Added code tags
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July 6th, 2009, 09:00 PM
|  | Moderator | | Join Date: Oct 2006 Location: Nashville, TN
Posts: 1,545
| | | re: Help with calcuations using imported numbers.
Please use code tags when posting code. See this link.
What is delta.days?
Access the list My_High like this: |
July 6th, 2009, 09:30 PM
| | Newbie | | Join Date: Jul 2009
Posts: 22
| | | re: Help with calcuations using imported numbers.
delta.days is just the number of days in between two dates... -
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today = datetime.date.today()
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date_format = "%m/%d/%Y"
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d0 = date(2009, 6, 21)
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d1 = today
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delta = d1-d0
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print delta.days
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I have this as my code now... -
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f = open("C:\users\cory\desktop\Verification.csv")
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dd = ['My_Highs']
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keys = f.readline().strip().split(',')
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for key in keys:
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dd.setdefault(key, ['My_Highs'])
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for line in f:
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for i, item in enumerate(line.strip().split(',')):
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dd[keys[i]].append(int(item))
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f.close()
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...and I am getting this error message...Attribute Error: 'list' object has no attribute 'setdefault'
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July 6th, 2009, 09:51 PM
| | Moderator | | Join Date: Oct 2006 Location: Nashville, TN
Posts: 1,545
| | | re: Help with calcuations using imported numbers.
Evidently you did not look at the code to understand what is happening. I will attempt to explain with embedded comments: - # Create an open file object for reading.
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f = open('your_file.csv')
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# Initialize an empty dictionary.
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dd = {}
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# Read the first line in the file.
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# These are the column labels.
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# We will use these labels as the dictionary keys.
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# Create a list by splitting the string on the comma.
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keys = f.readline().strip().split(',')
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# Iterate on the list of labels.
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for key in keys:
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# Using dictionary method setdefault, assign each dictionary
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# key to an empty list.
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dd.setdefault(key, [])
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# Iterate on the file object.
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# This iteration begins with line 2 because we already read the first line.
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for line in f:
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# Create a list of scores out of each line by splitting the string
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# on the comma character. Iterate on the list of scores.
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for i, item in enumerate(line.strip().split(',')):
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# Append each score to the value of the corresponding
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# dictionary key. Type cast the score to int.
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dd[keys[i]].append(int(item))
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# Close the file object.
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f.close()
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# Iterate on the list of keys (labels).
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for key in keys:
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# Print the key and corresponding dictionary value.
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print "%s: %s" % (key, dd[key])
Study the comments above and post your question again.
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July 6th, 2009, 10:15 PM
| | Newbie | | Join Date: Jul 2009
Posts: 22
| | | re: Help with calcuations using imported numbers.
The comments helped a lot, I figured it out! Thanks for all your help.
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July 6th, 2009, 10:45 PM
| | Moderator | | Join Date: Oct 2006 Location: Nashville, TN
Posts: 1,545
| | | re: Help with calcuations using imported numbers.
You are welcome. I think you learned something.
-BV
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July 6th, 2009, 10:59 PM
| | Newbie | | Join Date: Jul 2009
Posts: 22
| | | re: Help with calcuations using imported numbers.
I did! This is only my third day working with python, and I have never written code before so I will more than likely have some more questions with due time.
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