Accessing a value in tuple

Question

I need some assistance in accessing the values or entries inside the Tuple.

Consider the following data:

('{"email": "test@example.com"}',)
<type 'tuple'>
{"email": "test@example.com"}
<type 'str'>

First it was basically a Tuple.

After further processing, it is being converted to "str:.

You can have a look at following code.

So here I need to get the value for "email".

I tried the following code

rows = cur.fetchall()

for row in rows:
    print  row
    print type(row)

    for rowitems in row:

            print rowitems
            print type(rowitems)

Some one let me the way for the same.

What does your code have to do with the question? What is your input and what is your desired output? Please provide a complete, unambiguous example of what you want. — timgeb, Feb 01 '16 at 07:31
@timgeb it looks like he needs to convert the tuple values from a string to a dictionary. I'm on my phone, but I would think he wants `dict(row[0])['email']` — Jason, Feb 01 '16 at 07:34
Do you know how that string was created in the first place? At first glance it **could** be JSON, but there isn't really all that much context here. — Martijn Pieters, Feb 01 '16 at 07:34
@Jason: no, `dict()` does not take a string value like that. — Martijn Pieters, Feb 01 '16 at 07:34
As for the tuple, that's because you are running a SQL query; results are *always* a sequence of columns. Your query here has only one column, hence a tuple with just one value. — Martijn Pieters, Feb 01 '16 at 07:35
@Martijn thanks. I wasn't sure and I couldn't test it real quick. I know Python can easily convert some types. — Jason, Feb 01 '16 at 07:36
My second guess would have been `eval`. http://stackoverflow.com/questions/988228/converting-a-string-to-dictionary — Jason, Feb 01 '16 at 07:39

score 3 · Answer 1 · answered Feb 01 '16 at 07:33

3

You can use json.loads to parse the string to JSON.

Example

>>> import json
>>> a_tuple = ('{"email": "test@example.com"}',)
>>> [ json.loads(value)['email'] for value in a_tuple ]
[u'test@example.com']

This will give you a list of emails from the a_tuple

answered Feb 01 '16 at 07:33

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Here's another alternative: http://stackoverflow.com/questions/988228/converting-a-string-to-dictionary – Jason Feb 01 '16 at 07:41
3

@Jason: note the quotes contained in that string and in this one. The double quotes make this far more likely to be JSON. If Python's `repr()` output had been recorded in the database, then single quotes would have been generated and that other post would have absolutely applied. – Martijn Pieters Feb 01 '16 at 07:44
@Martijn would it matter in this case? `literal_eval` would covert it since it is a valid Python command? – Jason Feb 01 '16 at 07:55
1

@Jason: if this is JSON, then yes, it does matter, because as soon as there are boolean values, nulls or non-ASCII code-points in the string encoded to `\uhhhh` escapes, then `ast.literal_eval()` will either fail or produce invalid results. – Martijn Pieters Feb 01 '16 at 08:10

Accessing a value in tuple

1 Answers1