PYTHON - FOR inside FOR

Question

I’m performing a select on DB with the Python and treating this return. My doubt is in the use of a for within other’s for, use the script below:

import mysql.connector

mydb = mysql.connector.connect(
                                user='root',
                                host='localhost',
                                password='***')

mycursor = mydb.cursor()

mycursor.execute("select calldate, clid, src, dst from cdr.cdr \
where calldate like '2019-02-18%'\
ORDER BY calldate desc limit 2")

myresult = mycursor.fetchall()

for row in myresult:
    for fild in row:
        print (fild[0])
        print (fild[1])
        print (fild[2])
        print (fild[3])

mydb.close()

And the following error is being displayed:

# python3.6 dumpMysql.py
Traceback (most recent call last):
  File "dumpMysql.py", line 18, in <module>
    print (fild[0])
TypeError: 'datetime.datetime' object is not subscriptable

I’m trying to get the output be it:

Primeira linha do select
campo0
campo1
campo2
campo3

Segunda linha do select
campo0
campo1
campo2
campo3

Answer 1

To get this result, write the iteration like this:

for row in myresult:
    for fild in row:
        print (fild)

Why? Your code gets every row contained in myresult and then in each row he catches a fild at a time. For each fild that he picks up, makes a print(fild) onscreen.

You don’t have to put fild[0]...fild[3], only fild even.

Answer 2

By the comments you need to "save" the Fields in variables for further treatment, so the suggestion is to store these Fields in a dictionary, actually in a list of dictionaries (a dictionary for each Row):

lst_dicts = []
for row in myresult:
    d = {}
    d['calldate'] = row[0] 
    d['clid'] = row[1] 
    d['src'] = row[2] 
    d['dst'] = row[3] 
    lst_dicts.append(d)

At the end you will have a list of dictionaries, each with 4 keys/value, represented the names of the fields and their respective values within each line in myresult.