How to print list item + integer/string using logging in Python

Question

I'd like to print list item with the index of item such as

0: [('idx', 10), ('degree', 0)]
1: [('idx', 20), ('degree', 0)]

Based on the code below, how can I append '0:' as integer + string + list item?

import logging

class Node(object):
    __slots__= "idx", "degree"

    def __init__(self, idx, degree):
        self.idx = idx
        self.degree = 0


    def items(self):
        "dict style items"
        return [
            (field_name, getattr(self, field_name))
            for field_name in self.__slots__]

def funcA():

    a = []
    a.append(Node(10, 0))
    a.append(Node(20, 0))

    for i in range(0, len(a)):
        logging.debug(a[i].items())

if __name__ == '__main__':
    logging.basicConfig(level=logging.DEBUG)  
    funcA()

Currently, result is

DEBUG:root:[('idx', 10), ('degree', 0)]
DEBUG:root:[('idx', 20), ('degree', 0)]

Expecting

DEBUG:root:0:[('idx', 10), ('degree', 0)]
DEBUG:root:1:[('idx', 20), ('degree', 0)]

Answer 1

with Python > 3.6 you can use fstring

logging.debug(f"{i}:{a[i].items()}")

Answer 2

I would do it like this.

def funcA():
    a = []
    a.append(Node(10, 0))
    a.append(Node(20, 0))

    for i in range(0, len(a)):
        message = '%s:%s' % (i, a[i].items())
        logging.debug(message)

Which produces this as output:

DEBUG:root:0:[('idx', 10), ('degree', 0)]
DEBUG:root:1:[('idx', 20), ('degree', 0)]

You could also use join:

message = ':'.join([str(i), str(a[i].items())])

Or format:

message = '{0}:{1}'.format(str(i), a[i].items())

Whatever is the most clear to you.