Point_24/test.py

import math

def split_exp(expression):  # 将表达式拆分为数字、运算符和三角函数
    stack = []
    current_item = ''
    for char in expression:
        if char.isdigit() or char == '.':
            current_item += char
        elif char.isalpha():  # 识别字母表示的函数名
            current_item += char
        elif char == '(':
            if current_item:
                stack.append(current_item)
                current_item = ''
            stack.append(char)
        elif char == ')' and current_item:
            stack.append(current_item)
            stack.append(char)
            current_item = ''
        elif char in OPS:
            if current_item:
                stack.append(current_item)
                current_item = ''
            stack.append(char)
    if current_item:
        stack.append(current_item)
    return stack

def get_postfix_expression(expression):
    # 多位数拆分
    expression = split_exp(expression)
    precedence = {'+': 1, '-': 1, '*': 2, '/': 2, '^': 3,"sin":4,"cos":4,"tan":4}
    postfix = []
    stack = []
    def is_number(char):
        try:
            float(char)
            return True
        except ValueError:
            return False
    for char in expression:
        if is_number(char):
            postfix.append(char)
        elif char == '(':
            stack.append(char)
        elif char == ')':
            while stack and stack[-1] != '(':
                postfix.append(stack.pop())
            stack.pop()  # 弹出 '('
        elif char in precedence:
            while stack and stack[-1] != '(' and precedence.get(stack[-1], 0) >= precedence.get(char, 0):
                postfix.append(stack.pop())
            stack.append(char)
        # elif char in ('sin', 'cos', 'tan'):  # 处理三角函数
        #     stack.append(char)

    while stack:
        postfix.append(stack.pop())

    return postfix





exp = 'sin(3.3)^2+cos(3.3)^2'
OPS = ['+', '-', '*', '/', '^']

exp_ls = split_exp(exp)
print(exp_ls)
print(get_postfix_expression(exp))  # ['3.3', 'sin', '2', '^', '3.3', 'cos', '2', '^', '+']