Implementing array of structures( similar to C) in python by reading data from a file

Question

i want to implement the following in python, in C, it is like below, there is a structure

struct xyz {
char name[50];
char type[50];
char link[50];
char level[50];
}XYZ;

And i have created an array of this struct xyz as following:

XYZ array[] = 
{ {"Mac", "char", "list","one"},
  {"John", "char", "list","three"},
  ...
  ...
};

and accessing these by array[0], array[1] etc. In python script, suppose i have listed these array elements in a text file like below, e.g. file.txt

Mac, char, list, one
John, char, list, three
...
...

Now i have to read the file.txt, and store them into my python script similar to array of structs and access accordingly.

Burhan Khalid · Accepted Answer · 2013-07-01 06:55:39Z

1

import csv

with open('somefile.txt') as f:
   reader = csv.reader(f, delimiter=',')
   lines = list(reader)

print(lines)

answered Jul 1, 2013 at 6:55

Burhan Khalid

175k20 gold badges254 silver badges291 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

asafge · Accepted Answer · 2013-07-01 07:17:16Z

1

On top of what was suggested here, you might want to take advantage of the fact that Python can do OOP (as opposed to C), so adding to Burjan's answer, I would do something like:

class xyz():
def __init__(self, name, type):
    self.name = name
    self.type = type
    // etc

And then call something like result = [ xyz(*line) for line in lines ]

answered Jul 1, 2013 at 7:17

asafge

1,1391 gold badge14 silver badges21 bronze badges

Comments

mishik · Accepted Answer · 2013-07-01 07:06:34Z

0

Your syntax is a bit off.

This will create an array of arrays of 4 values:

XYZ = [ 
    ["Mac", "char", "list","one"],
    ["John", "char", "list","three"],
    ...
    ...
]

This will create an array of objects with 4 fields:

XYZ = [ 
    {"name": "Mac", "type": "char", "link": "list", "level": "one"},
    {"name": "John", "type": "char", "link": "list", "level": "three"},
    ...
    ...
]

To read this data from file into structure like #2:

import csv

XYZ = []
with open("data.csv") as csv_data:
    entries = csv.reader(csv_data, delimiter=",")
    # This can be done with list comprehension, but will be difficult to read
    for entry in entries:
        XYZ.append({
            "name": entry[0],
            "type": entry[1],
            "link": entry[2],
            "level": entry[3]
        })

edited Jul 1, 2013 at 7:06

answered Jul 1, 2013 at 6:53

mishik

10k9 gold badges48 silver badges69 bronze badges

6 Comments

torek Over a year ago

His syntax is C, not Python, which is why it looks so odd as Python. :D

Baijnath Jaiswal Over a year ago

thanks a lot,it is similar to what i was trying to do but how would i get the corresponding value? meaning if i search the string 'Mac' in XYZ, and if found then i need the corresponding type, link and level at the same time..

mishik Over a year ago

if you need to search for "name=Mac": [entry for entry in XYZ if entry.name == "Mac"] will return you the list of corresponding entries.

Baijnath Jaiswal Over a year ago

Please don't mind, i am a beginner i python[entry for entry in XYZ if entry.name == "Mac"] AttributeError: 'dict' object has no attribute 'name'

Baijnath Jaiswal Over a year ago

working but i am not getting the right values, it prints the values of last index e.g. char, John, list, three

|

John La Rooy · Accepted Answer · 2013-07-03 12:35:38Z

0

import csv

from collections import namedtuple
XYZ = namedtuple('xyz', ['name', 'type', 'link', 'level'])

with open('somefile.txt') as f:
   reader = csv.reader(f, delimiter=',')
   lines = [XYZ(*line) for line in reader]

for item in lines:
    print(item.name)
    print(item.type)
    #etc.

edited Jul 3, 2013 at 12:35

answered Jul 1, 2013 at 7:12

John La Rooy

306k54 gold badges378 silver badges513 bronze badges

2 Comments

Baijnath Jaiswal Over a year ago

thanks, i tried it but getting error: lines = [XYZ(line) for line in reader] TypeError: __new__() takes exactly 5 arguments (2 given)

John La Rooy Over a year ago

@Jaiswal, that should be lines = [XYZ(*line) for line in reader]

Collectives™ on Stack Overflow

Implementing array of structures( similar to C) in python by reading data from a file

4 Answers 4

Comments

Comments

6 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

6 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related