How do I extract data from a column in csv file in python in relation to the row it's in?-CodePudding

I am trying to extract data from a csv file that look something like this:

ID,Name,Grade
23,Abby,A
56,Amy,D
13,Kate,C
74,Peter,B
45,Mike,D
19,Sev,D
48,Lily,C
30,Harry,F

I have folders set up by the order of the grade. I want to scan the csv file and extract the information and place each name as a subfolder under the corresponding grade folder. I want the end result to look something like this:

I am planning on using pandas for this, and all I have right now is this:

# Open file 
with open('Students.csv') as file_obj:
      
    # Create reader object by passing the file 
    # object to reader method
    reader_obj = csv.reader(file_obj)
      
    # Iterate over each row in the csv 
    # file using reader object
    for row in reader_obj:
        print(row)

I know this is really vague, but I really don't know how to make it better.

CodePudding user response：

You certainly don't need pandas for this. A simple dictionary will do it.

import csv
      
reader_obj = csv.reader(open('x.csv'))
grades = {
    'A':[],
    'B':[],
    'C':[],
    'D':[],
    'F':[]
}

for row in reader_obj:
    if row[0] == 'ID':
        continue
    grades[row[2]].append( row[1] )

for k,v in grades.items():
    print(k)
    for name in v:
        print("   ",name)

Output:

A
    Abby
B
    Peter
C
    Kate
    Lily
D
    Amy
    Mike
    Sev
F
    Harry

You could simplify this using a defaultdict, but I'm not sure it's worth the trouble.

CodePudding user response：

At the time you call print, row[0] is the id, row[1]is the name, and row[2] is the grade. Now work out a function that takes a name and a grade as arguments, and creates the corresponding directory; call it instead of print, and you’re done.

CodePudding user response：

You can use the csv module to parse the CSV, and then use the os module to create the subdirectories:

import os
import csv
import itertools

with open("data.csv") as csvfile:
    data = list(csv.DictReader(csvfile))
    grades = set(row["Grade"] for row in data)

    for grade in grades:
        os.mkdir(grade)

    for row in data:
        os.mkdir(f"{row['Grade']}{os.path.sep}{row['Name']}")

This produces the desired directory structure: