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python csv into dictionary

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python

csv

I am pretty new to python. I need to create a class that loads csv data into a dictionary.

I want to be able to control the keys and value So let say the following code, I can pull out worker1.name or worker1.age anytime i want.

class ageName(object):
'''class to represent a person'''
def __init__(self, name, age):
self.name = name
self.age = age

worker1 = ageName('jon', 40)
worker2 = ageName('lise', 22)

#Now if we print this you see that it`s stored in a dictionary
print worker1.__dict__
print worker2.__dict__
#
'''
{'age': 40, 'name': 'jon'}
#
{'age': 22, 'name': 'lise'}
#
'''
#

#when we call (key)worker1.name we are getting the (value)
print worker1.name
#
'''
#
jon
#
'''

But I am stuck at loading my csv data into keys and value.

[1] I want to create my own keys worker1 = ageName([name],[age],[id],[gender])

[2] each [name],[age],[id] and [gender] comes from specific a column in a csv data file

I really do not know how to work on this. I tried many methods but I failed. I need some helps to get started on this.

---- Edit This is my original code

import csv

# let us first make student an object

class Student():
    def __init__(self):
        self.fname = []
        self.lname = []
        self.ID = []
        self.sport = []
        # let us read this file
        for row in list(csv.reader(open("copy-john.csv", "rb")))[1:]:
            self.fname.append(row[0])
            self.lname.append(row[1])   
            self.ID.append(row[2])
            self.sport.append(row[3])
    def Tableformat(self):
        print "%-14s|%-10s|%-5s|%-11s" %('First Name','Last Name','ID','Favorite Sport')
        print "-" * 45
        for (i, fname) in enumerate(self.fname):
           print "%-14s|%-10s|%-5s|%3s" %(fname,self.lname[i],self.ID[i],self.sport[i])
    def Table(self):
        print self.lname

class Database(Student):
    def __init__(self):
        g = 0
        choice = ['Basketball','Football','Other','Baseball','Handball','Soccer','Volleyball','I do not like sport']
        data = student.sport
        k = len(student.fname)
        print k
        freq = {}
        for i in data:
            freq[i] = freq.get(i, 0) + 1
        for i in choice:
            if i not in freq:
                freq[i] = 0
            print i, freq[i]


student = Student()
database = Database()

This is my current code (incomplete)

import csv
class Student(object):
    '''class to represent a person'''
    def __init__(self, lname, fname, ID, sport):
        self.lname = lname
        self.fname = fname
        self.ID = ID
        self.sport = sport
reader = csv.reader(open('copy-john.csv'), delimiter=',', quotechar='"')
student = [Student(row[0], row[1], row[2], row[3]) for row in reader][1::]
print "%-14s|%-10s|%-5s|%-11s" %('First Name','Last Name','ID','Favorite Sport')
print "-" * 45
for i in range(len(student)):
    print "%-14s|%-10s|%-5s|%3s" %(student[i].lname,student[i].fname,student[i].ID,student[i].sport)

choice = ['Basketball','Football','Other','Baseball','Handball','Soccer','Volleyball','I do not like sport']
lst = []
h = 0
k = len(student)
# 23
for i in range(len(student)):
    lst.append(student[i].sport) # merge together

for a in set(lst):
    print a, lst.count(a)

for i in set(choice):
    if i not in set(lst):
        lst.append(i)
        lst.count(i) = 0
        print lst.count(i)
like image 267
CppLearner Avatar asked Dec 14 '09 00:12

CppLearner


People also ask

How do I convert a CSV file to a dictionary in Python?

The best way to convert a CSV file to a Python dictionary is to create a CSV file object f using open("my_file. csv") and pass it in the csv. DictReader(f) method. The return value is an iterable of dictionaries, one per row in the CSV file, that maps the column header from the first row to the specific row value.

How do I save a CSV file as a dictionary?

Easiest way is to open a csv file in 'w' mode with the help of open() function and write key value pair in comma separated form. The csv module contains DictWriter method that requires name of csv file to write and a list object containing field names.

How do you make a list into a dictionary?

To convert a list to dictionary, we can use list comprehension and make a key:value pair of consecutive elements. Finally, typecase the list to dict type.


2 Answers

import csv

reader = csv.reader(open('workers.csv', newline=''), delimiter=',', quotechar='"')
workers = [ageName(row[0], row[1]) for row in reader]

workers now has a list of all the workers

>>> workers[0].name
'jon'

added edit after question was altered

Is there any reason you're using old style classes? I'm using new style here.

class Student:
    sports = []
    def __init__(self, row):
       self.lname, self.fname, self.ID, self.sport = row
       self.sports.append(self.sport)
    def get(self):
       return (self.lname, self.fname, self.ID, self.sport)

reader = csv.reader(open('copy-john.csv'), delimiter=',', quotechar='"')
print "%-14s|%-10s|%-5s|%-11s" % tuple(reader.next()) # read header line from csv
print "-" * 45
students = list(map(Student, reader)) # read all remaining lines
for student in students:
    print "%-14s|%-10s|%-5s|%3s" % student.get()

# Printing all sports that are specified by students
for s in set(Student.sports): # class attribute
    print s, Student.sports.count(s)

# Printing sports that are not picked 
allsports = ['Basketball','Football','Other','Baseball','Handball','Soccer','Volleyball','I do not like sport']
for s in set(allsports) - set(Student.sports):
    print s, 0

Hope this gives you some ideas of the power of python sequences. ;)

edit 2, shortened as much as possible... just to show off :P

Ladies and gentlemen, 7(.5) lines.

allsports = ['Basketball','Football','Other','Baseball','Handball',
             'Soccer','Volleyball','I do not like sport']
sports = []
reader = csv.reader(open('copy-john.csv'))
for row in reader:
    if reader.line_num: sports.append(s[3])
    print "%-14s|%-10s|%-5s|%-11s" % tuple(s)
for s in allsports: print s, sports.count(s)
like image 154
Emmanuel Avatar answered Oct 23 '22 11:10

Emmanuel


I know this is a pretty old question, but it's impossible to read this, and not think of the amazing new(ish) Python library, pandas. Its main unit of analysis is a think called a DataFrame which is modelled after the way R handles data.

Let's say you have a (very silly) csv file called example.csv which looks like this:

day,fruit,sales
Monday,Banana,10
Monday,Orange,20
Tuesday,Banana,12
Tuesday,Orange,22

If you want to read in a csv in double-quick time, and do 'stuff' with it, you'd be hard pressed to beat the following code for either brevity or ease of use:

>>> import pandas as pd
>>> csv = pd.read_csv('example.csv')
>>> csv
       day   fruit  sales
0   Monday  Banana     10
1   Monday  Orange     20
2  Tuesday  Banana     12
3  Tuesday  Orange     22
>>> csv[csv.fruit=='Banana']
       day   fruit  sales
0   Monday  Banana     10
2  Tuesday  Banana     12
>>> csv[(csv.fruit=='Banana') & (csv.day=='Monday')]
      day   fruit  sales
0  Monday  Banana     10

In my opinion, this is really fantastic stuff. Never iterate over a csv.reader object again!

like image 30
LondonRob Avatar answered Oct 23 '22 12:10

LondonRob