Python 通过latex 字符串从 Sympy 生成 SinCosTan 值

Sympy的三角函数自动计算最重要的弧度值.例如，sin(pi / 4)的计算结果为sqrt(2)/2.由于您提供的是学位Angular ，因此不应进行判断.例如:

from sympy import *
from sympy.parsing.latex import parse_latex
s = r"\sin(30) + \cos\left(45\right)"
expr = parse_latex(s)
expr
# out: sin(30) + cos(45)

此时，您可以对expr进行后处理，以将三角函数的参数从度转换为弧度:

from sympy.functions.elementary.trigonometric import TrigonometricFunction

# finds all trigonometric functions
trigs = expr.find(TrigonometricFunction)

# loop over each match, replace it with a new trig function with angle in radians
for t in trigs:
    expr = expr.replace(t, t.func(t.args[0] * pi / 180))
expr
# out: 1/2 + sqrt(2)/2

编辑:您可能只想在三角函数的参数为数字时应用替换.如果是这样的话:

s = r"\sin(30) + \cos\left(45\right) + \cos(x)"
expr = parse_latex(s)
for t in trigs:
    if t.args[0].is_Number:
        expr = expr.replace(t, t.func(t.args[0] * pi / 180))
expr
# out: cos(x) + 1/2 + sqrt(2)/2

最终编辑:要考虑反三角函数，请执行以下操作:

from sympy.functions.elementary.trigonometric import InverseTrigonometricFunction

s = r"\arcsin(0) + \arccos(1/2)"
expr = parse_latex(s)

inverse_trigs = expr.find(InverseTrigonometricFunction)

# loop over each match, replace it with a new inverse trig function
for t in inverse_trigs:
    expr = expr.replace(t, t * 180 / pi)
expr
# out: 180*asin(0)/pi + 180*acos(1/2)/pi