在python中将字符串转换为元组

Question

I have a string returnd from a software like "('mono')" from that I needed to convert string to tuple .

that I was thinking using ast.literal_eval("('mono')") but it is saying malformed string.

Answer 1

Since you want tuples, you must expect lists of more than element in some cases. Unfortunately you don't give examples beyond the trivial (mono) , so we have to guess. Here's my guess:

"(mono)"
"(two,elements)"
"(even,more,elements)"

If all your data looks like this, turn it into a list by splitting the string (minus the surrounding parens), then call the tuple constructor. Works even in the single-element case:

assert data[0] == "(" and data[-1] == ")"
elements = data[1:-1].split(",")
mytuple = tuple(elements)

Or in one step: elements = tuple(data[1:-1].split(",")) . If your data doesn't look like my examples, edit your question to provide more details.

Answer 2

How about using regular expressions ?

In [1686]: x
Out[1686]: '(mono)'

In [1687]: tuple(re.findall(r'[\w]+', x))
Out[1687]: ('mono',)

In [1688]: x = '(mono), (tono), (us)'

In [1689]: tuple(re.findall(r'[\w]+', x))
Out[1689]: ('mono', 'tono', 'us')

In [1690]: x = '(mono, tonous)'

In [1691]: tuple(re.findall(r'[\w]+', x))
Out[1691]: ('mono', 'tonous')

Answer 3

Try to this

a = ('mono')
print tuple(a)      # <-- you create a tuple from a sequence 
                    #(which is a string)
print tuple([a])    # <-- you create a tuple from a sequence 
                    #(which is a list containing a string)
print tuple(list(a))# <-- you create a tuple from a sequence 
                    #     (which you create from a string)
print (a,)# <-- you create a tuple containing the string
print (a)

Output :

('m', 'o', 'n', 'o')
('mono',)
('m', 'o', 'n', 'o')
('mono',)
mono

Answer 4

I assume that the desired output is a tuple with a single string: ('mono',)

A tuple of one has a trailing comma in the form (tup,)

a = '(mono)'
a = a[1:-1] # 'mono': note that the parenthesis are removed removed 
            # if they are inside the quotes they are treated as part of the string!
b = tuple([a]) 
b
> ('mono',)
# the final line converts the string to a list of length one, and then the list to a tuple

Answer 5

Convert string to tuple? Just apply tuple :

>>> tuple('(mono)')
('(', 'm', 'o', 'n', 'o', ')')

Now it's a tuple.