Why Does My Python Code Show 'SyntaxError: Invalid Syntax' on a Correct Line?

Why Do I Get "SyntaxError: Invalid Syntax" in a Line with Perfectly Valid Syntax?

In certain versions of Python, you may encounter a "SyntaxError: invalid syntax" even when a line of code appears to be correct. When this occurs, the error may persist even after removing the allegedly problematic line, and the error may shift to the following line.

This issue arises when there are unbalanced parentheses or other syntax errors in the preceding lines. To resolve the error,仔细examine the code before the reported error line.

For instance, consider the following code:

guess = Pmin+(Pmax-Pmin)*((1-w**2)*fi1+(w**2)*fi2)
fi2=0.460*scipy.sqrt(1-(Tr-0.566)**2/(0.434**2)+0.494
solution = scipy.optimize.newton(funcPsat,guess, args=(T,self))

In this example, the error occurs on the second line, but the actual issue is with the parentheses on the first line. The parentheses are unbalanced, with three open parentheses and only two close parentheses.

# 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

By correcting the parentheses in the first line, the "SyntaxError" should be resolved.

In summary, when encountering a "SyntaxError: invalid syntax" despite apparently valid syntax, check the preceding lines for any syntax errors, such as unbalanced parentheses or missing brackets. By meticulously examining the code, these errors can be rectified, ensuring proper syntax and error-free execution.

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