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Python - get elements from list

From a python function, I get the following output:
['(0.412169, mississippi)']
The type indicates that it is a list. I want to extract the values from the list and save it as separate elements. I tried various functions to convert list to tuple, list to str, extracting the element by Index from the tuple or str, nothing worked out. When I try to extract the element by index, I either get '(' for the first element index 0, or when I try to extract through a iterator function, I get all the values split up like the full data set as a string.
How do I get values separately.

You can iterate over your data, remove the parentheses using slicing and split the string by comma to create a list, which will be appended to your output payload:
data = ['(0.412169, mississippi)', '(0.412180, NY)']
extracted_values = []
for d in data:
extracted_values += d[1:-1].split(",")
print(extracted_values)
# output: ['0.412169', ' mississippi', '0.412180', ' NY']

Your list content a string, not a list.
If you want to extract the content of a string, use the "eval" statement
my_tuple = eval("(0.412169, 'mississippi')")
Note that the "eval" function can be dangerous, because if your string content python code, it could be executed.

How can I extract values from a list?

I am new to Python and am trying to achieve something new. I have a list defined with some string values, like
col_names = 'ABC,DEF,XYZ'.
If I want to extract and use values individually, how can I do that in Python?
Ex: I want to use ABC in one scenario but DEF in another and so on.
Can I create the list as a dictionary, like below? Would that help anything
col_names = {'ABC','DEF','XYZ'}

col_names is a string, not a list. You could use col_names.split(',') to separate each value.
FYI, the your second definition for col_names is a set, not a dictionary.
To use values from a list, you'd reference each value's index
For example, in a list ls = ['ABC','DEF','XYZ'], ls[2] would be equal to 'XYZ'

Outputting None instead of Values

I am trying to utilize list comprehension to populate a new list, which is the length of text in a DataFrame column.
So if the text is "electrical engineer", it should output 19 etc. Instead, it just fills the list with None values
I have written out list comprehension below
all_text_length = [all_text_length.append(len(i)) for i in data['all_text']]
Expecting output of integer but its None
As a workaround, I am currently using (successfully)
[all_text_length.append(len(i)) for i in data['all_text']]```

Read the documentation on append: it works in-place. There is no returned value. What you've written is essentially
all_text_length = [None for i in data['all_text']]
It appears that you're trying to make a list comprehension to entirely change your list. Try this:
all_text_length = [len(i) for i in data['all_text']]
If you just need the lengths in a convenient form, would it do to form a new column? Simply apply len to the df column.

The value before the "for" statement in the list comprehension, will be added to the list. If you place a statement in there, like
all_text_length.append(len(i)
, the return value of that function will be added. Because .append() doesnt have areturn-statement in it, you get the value None as return type, wich will be added to your list.
Use the code #Prune recommended and it should work as you want.

You are trying to append to the same list on which you are doing list comprehension. Since the append returns a None type, you are getting None. The below code should work,
all_text_length = map(len, data['all_text'])
map is a function that takes another function (first argument) and applies it to every element in an iterable (second argument) and returns a list of the results.

Splitting up a list with all values sitting in the same index in Python

Im pretty new to Python.
I have a list which looks like the following:
list = [('foo,bar,bash',)]
I grabbed it from and sql table (someone created the most rubbish sql table!), and I cant adjust it. This is literally the only format I can pull it in. I need to chop it up. I can't split it by index:
print list[0]
because that just literally gives me:
[('foo,bar,bash',)]
How can I split this up? I want to split it up and write it into another list.
Thank you.

list = [('foo,bar,bash',)] is a list which contains a tuple with 1 element. You should also use a different variable name instead of list because list is a python built in.
You can split that one element using split:
lst = [('foo,bar,bash',)]
print lst[0][0].split(',')
Output:
['foo', 'bar', 'bash']
If the tuple contains more than one element, you can loop through it:
lst = [('foo,bar,bash','1,2,3')]
for i in lst[0]:
print i.split(',')

Python list format from mysqldb

I'm trying to use a Class (adns-python) which is expecting a list in the format:
domain_names = ["google.com", "yahoo.com"]
This is working when I declare the list that way manually. However, I'm trying to use a list returned from mysql using python-mysqldb.
When I look at what is being returned from mysql using:
type(mysql_rows)
This also shows as a list, but when view the result:
print(mysql_rows)
I can see the list is in the format:
[('google.com',), ('yahoo.com',)]
I've tried forcing the output to a list again using list(mysql_rows) which didn't work. I've tried parsing the text manually to make it look like the list using:
text_rows = "[" + ", ".join'"%s"' % i for i in mysql_rows = "]"
Which then shows as the correct format, but it is a string not a list so this doesn't work either.
This is my first few days learning python, so I'm sorry if this is an obvious/stupid question.
Thanks

The list is a list of tuples. A simple
lst = [x for x, in mysql_rows]
should be sufficient.

mysql returns a list of tuples. Each tuple is a result row in your result set. If you want a list of only the first "column" in the result, try this:
first_column = [x[0] for x in mysql_rows]