Consolidation of stringified numerical comparisons

Question

I have list of comparisons against a variable like this

['x < 0.15', 'x > -inf', 'x < 0.20', 'x > -5.5']

How can these comparisons be consolidated to result '(-5.5, 0.15)' .

I see there's no data structure that supports representation of range of continuous real numbers in python

Answer 1

You can use sympy to solve system of inequalities:

In [1]: from sympy import oo, solve

In [2]: from sympy.abc import x

In [3]: from sympy.parsing.sympy_parser import parse_expr

In [4]: system = ['x < 0.15', 'x > -inf', 'x < 0.20', 'x > -5.5']

In [5]: solve([parse_expr(x, local_dict={'inf': oo}) for x in system])
Out[5]: (-5.5 < x) & (x < 0.15)

Answer 2

One way in pure Python:

myList = ['x < 0.15', 'x > -inf', 'x < 0.20', 'x > -5.5']


def andRange(lst):
    gt = []
    lt = []
    for rng in lst:
        if "<" in rng:
            strVal = rng.split("<")[1]
            if strVal.strip() != "inf":
                lt.append(float(strVal))
        if ">" in rng:
            strVal = rng.split(">")[1]
            if strVal.strip() != "-inf":
                gt.append(float(strVal))
    return (min(lt), max(gt))


print(andRange(myList))