How to Iterate through cur.fetchall() in Python

Question

I am working on database connectivity in Python 3.4. There are two columns in my database.

Below is the query which gives me all the data from two columns in shown f

Answer 1

As the output you given [('F:\\test1.py', '12345abc'), ('F:\\test2.py', 'avcr123')]

for i, row in data:
    print(i)  # i is column1's value
    print(row)# row is column's value

So you don't need row[i] or row[j], that was wrong, in that each step of that iteration

for i, row in data 

is the same as i, row = ('abc', 'def') it set abc to variable i and 'def' to row

BTW ,I don't know what database you use, if you use Mysql and python driverMySQL Connector, you can checkout this guide to fetch mysql result as dictionary you can get a dict in iteration, and the keys is your table fields' name. I think this method is convenient more.

Answer 2

To iterate over and print rows from cursor.fetchall() you'll just want to do:

for row in data:
    print row

You should also be able to access indices of the row, such as row[0], row[1], iirc.

Of course, instead of printing the row, you can manipulate that row's data however you need. Imagine the cursor as a set of rows/records (that's pretty much all it is).

Answer 3

looking at

[('F:\\test1.py', '12345abc'), ('F:\\test2.py', 'avcr123')]
  i              j                 i            j

you are taking a strings i and j and indexing it like

   print(row['F:\\test1.py'])
    print(row['12345abc'])

which gave you typeError

TypeError: string indices must be integers

this is because i in data is a string and your a indexing this

try this

for i,j in data:
    print(i)
    print(j)

Answer 4

To iterate through this: [('F:\test1.py', '12345abc'), ('F:\test2.py', 'avcr123')]

Code:
for i in data:
   print i[0] + '\t' + i[1]

Output:

F:\test1.py 12345abc
F:\test2.py avcr123

Answer 5

It looks like you have two colunms in the table, so each row will contain two elements.

It is easiest to iterate through them this way:

for column1, column2 in data:

That is the same as:

for row in data:
    column1, column2 = row

You could also, as you tried:

for row in data:
    print row[0] # or row[i]
    print row[1] # or row[j]

But that failed because you overwrote i with the value of first column, in this line: for i, row in data:.

EDIT

BTW, in general, you will never need this pattern in Python:

i = 0
for ...:
    ...
    i += 1

Instead of that, it is common to do simply:

for item in container:
    # use item

# or, if you really need i:
for i, item in enumerate(container):
    # use i and item