使用Python字典进行表/数据操作

Question

I need help finishing up this python script. I'm an intern at a company, and this is my first week. I was asked to develop a python script that will take a .csv and put(append) any related columns into one column so that they have only the 15 or so necessary columns with the data in them. For example, if there are zip4, zip5, or postal code columns, they want those to all be underneath the zip code column.

I just started learning python this week as I was doing this project so please excuse my noobish question and vocabulary. I'm not looking for you guys to do this for me. I'm just looking for some guidance. In fact, I want to learn more about python, so anyone who could lead me in the right direction, please help.

I'm using dictionary key and values. The keys are every column in the first row. The values of each key are the remaining rows(second through 3000ish). Right now, I'm only getting one key:value pair. I'm only getting the final row as my array of values, and I'm only getting one key. Also, I'm getting a KeyError message, so my key's aren't being identified correctly. My code so far is underneath. I'm gonna keep working on this, and any help is immensely appreciated! Hopefully, I can by the person who helps me a beer and I can pick their brain a little:)

Thanks for your time

# To be able to read csv formated files, we will frist have to import the csv module
import csv

# cols = line.split(',')# each column is split by a comma
#read the file
CSVreader = csv.reader(open('N:/Individual Files/Jerry/2013 customer list qc, cr, db, gb 9-19-2013_JerrysMessingWithVersion.csv', 'rb'), delimiter=',', quotechar='"')

# define open dictionary
SLSDictionary={}# no empty dictionary. Need column names to compare to. 


i=0
#top row are your keys. All other rows are your values

#adjust loop
for row in CSVreader:
# mulitple loops needed here
    if i == 0:
            key = row[i]
    else:
            [values] = [row[1:]]
            SLSDictionary = dict({key: [values]}) # Dictionary is keys and array of values
    i=i+1


#print Dictionary to check errors and make sure dictionary is filled with keys and values        
print SLSDictionary

# SLSDictionary has key of zip/phone plus any characters
#SLSDictionary.has_key('zip.+')
SLSDictionary.has_key('phone.+')

#value of key are set equal to x. Values of that column set equal to x
#[x]=value

#IF SLSDictionary has the key of zip plus any characters, move values to zip key
#if true:   
#        SLSDictionary['zip'].append([x])
    #SLSDictionary['phone_home'].append([value]) # I need to append the values of the specific column, not all columns
    #move key's values  to correct, corresponding key
SLSDictionary['phone_home'].append(SLSDictionary[has_key('phone.+')])#Append the values of the key/column 'phone plus characters' to phone_home key/column in SLSDictionary
#if false:
#        print ''
    # go to next key

SLSDictionary.has_value('')

if true:
    print 'Error: No data in column'

# if there's no data in rows 1-?. Delete column
#if value <= 0:
#        del column

print SLSDictionary 

Answer 1

Found a couple of errors just quickly looking at it. One thing you need to watch out for is that you're assigning a new value to the existing dictionary every time:

SLSDictionary = dict({key: [values]})

You're re-assigning a new value to your SLSDictionary every time it enters that loop. Thus at the end you only have the bottom-most entry. To add a key to the dictionary you do the following:

SLSDictionary[key] = values

Also you shouldn't need the brackets in this line:

[values] = [row[1:]]

Which should instead just be:

values = row[1:]

But most importantly is that you will only ever have one key because you constantly increment your i value. So it will only ever have one key and everything will constantly be assigned to it. Without a sample of how the CSV looks I can't instruct you on how to restructure the loop so that it will catch all the keys.

Assuming your CSV is like this as you've described:

Col1, Col2, Col3, Col4
Val1, Val2, Val3, Val4
Val11, Val22, Val33, Val44
Val111, Val222, Val333, Val444

Then you probably want something like this:

dummy = [["col1", "col2", "col3", "col4"],
         ["val1", "val2", "val3", "val4"],
         ["val11", "val22", "val33", "val44"],
         ["val111", "val222", "val333", "val444"]]

column_index = []
SLSDictionary = {}

for each in dummy[0]:
    column_index.append(each)
    SLSDictionary[each] = []

for each in dummy[1:]:
    for i, every in enumerate(each):
        try:
            if column_index[i] in SLSDictionary.keys():
                SLSDictionary[column_index[i]].append(every)
        except:
            pass

print SLSDictionary

Which Yields...

{'col4': ['val4', 'val44', 'val444'], 'col2': ['val2', 'val22', 'val222'], 'col3': ['val3', 'val33', 'val333'], 'col1': ['val1', 'val11', 'val111']}

If you want them to stay in order then change the dictionary type to OrderedDict()