‘Syntax Error: invalid syntax’ for no apparent reason

I’ve been trying to get a fix and can’t find why the error keeps appearing. Pmin,Pmax,w,fi1 and fi2 have all been assigned finite values

guess=Pmin+(Pmax-Pmin)*((1-w**2)*fi1+(w**2)*fi2)

When i remove this line from the code, the same error appears at the next line of code, again for no reason I can think of

Edit: Here is the chunk of code I was referring to:

def Psat(self, T):
    pop= self.getPborder(T)
    boolean=int(pop[0])

    P1=pop[1]
    P2=pop[2]
    if boolean:
        Pmin = float(min([P1, P2]))
        Pmax = float(max([P1, P2]))
        Tr=T/self.typeMolecule.Tc
        w=0.5*(1+scipy.tanh((10**5)*(Tr-0.6)))
        fi1=0.5*(1-scipy.tanh(8*((Tr**0.4)-1)))
        fi2=0.460*scipy.sqrt(1-(Tr-0.566)**2/(0.434**2)+0.494

        guess = Pmin+(Pmax-Pmin)*((1-w**2)*fi1+(w**2)*fi2)   #error here

        solution = scipy.optimize.newton(funcPsat,guess, args=(T,self))

Answers:

Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

For problems where it seems to be an error on a line you think is correct, you can often remove/comment the line where the error appears to be and, if the error moves to the next line, there are two possibilities:

• Either both lines have a problem (and the second may have been hidden by the first); or
• The previous line has a problem which is being carried forward.

The most likely case is the second option (even more so if you remove another line and it moves again).

For example, the following Python program twisty_passages.py:

xyzzy = (1 +
plugh = 7

generates the error:

  File "twisty_passages.py", line 2
    plugh = 7
          ^
SyntaxError: invalid syntax

despite the problem clearly being on line 1.

In your particular case, that second case is the zctual problem. The parentheses in the line before your error line are unmatched, as per the following annotated snippet:

# open parentheses: 1  2             3
#                   v  v             v
fi2=0.460*scipy.sqrt(1-(Tr-0.566)**2/(0.434**2)+0.494
#                               ^             ^
# close parentheses:            1             2

Depending on what you’re trying to achieve, the solution may be as simple as just adding another closing parenthesis at the end, to close off the sqrt function.

I can’t say for certain since I don’t recognise the expression off the top of my head. Hardly surprising if (assuming PSAT is the enzyme, and the use of the typeMolecule identifier) it’s to do with molecular biology – I seem to recall failing Biology consistently in my youth 🙂

Method 2

If you are running the program with python, try running it with python3.

Method 3

You’re missing a close paren in this line:

fi2=0.460*scipy.sqrt(1-(Tr-0.566)**2/(0.434**2)+0.494

There are three ( and only two ).

Method 4

I encountered a similar problem, with a syntax error that I knew should not be a syntax error. In my case it turned out that a Python 2 interpreter was trying to run Python 3 code, or vice versa; I think that my shell had a PYTHONPATH with a mixture of Python 2 and Python 3.

Method 5

I noticed that invalid syntax error for no apparent reason can be caused by using space in:

print(f'{something something}')

Python IDLE seems to jump and highlight a part of the first line for some reason (even if the first line happens to be a comment), which is misleading.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0