how to you evaluate a string and the words that you can't evaluate keep the same?
string = input() string = (''.join([str(eval(s)) if ('(' in s and ')' in s) else s for s in string.split(' ')])) print(string) with this code there are some problems:
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if I write 5-(2-sp.sqrt(4)) it will give me an EOF error because it will split the words in a way that sp.sqrt(4) will be sp.sqrt(4)). It should be sp.sqrt(4)
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if i write ‘2-10’ it won’t evaluate it and will just return ‘2-10’; it should return ‘-8’. While if I write ‘2-10*(2-5)’ it will return the write answer.
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instead of just don’t evaluate the part that the code doesn’t recognize, it will give me an error saying that the part not recognized isn’t defined. (ex. ‘2+x-10-(5*10)’ —- name ‘x’ is not defined. It should return: ‘x-58’
Issue – 1:
it will give me an EOF error because it will split the words in a way that sp.sqrt(4) will be sp.sqrt(4))
- No, it doesn’t split the string that way because you are splitting the string using ‘ ‘, so the output for the split function will be
['5-(2-sp.sqrt(4))'] - It won’t give an error unless and until your input has a valid python expression (in this case, I suspect the issue is with
sp)
Issue – 2:
if I write ‘2-10’ it won’t evaluate it and will just return ‘2-10’ but when I write ‘2-10*(2-5)’ it will return the write answer.
It is because you have called the eval() function only if there are both ‘(‘ and ‘)’
Issue – 3:
It is because eval() takes only valid python expressions ( you can’t put an un-declared variable directly inside the parameter). In your case x was not declared before.
Solution:
There is a sympy function parse_expr which probably does what you want here:
In [20]: from sympy import parse_expr In [21]: parse_expr('5-(2-sqrt(4))') Out[21]: 5 In [22]: parse_expr('2-10') Out[22]: -8 In [23]: parse_expr('2+x-10-(5*10)') Out[23]: x - 58 
