小案例-01-字符串转计算公式

<code class="javascript">dict_input_1 = {'P1': 1, 'P2': 2, 'P3': 3, 'P4': 4, 'P5': 15}dict_input_2 = {'P1': 3, 'P2': 2, 'P3': 3, 'P4': 4, 'P5': 5}dict_input_3 = {'P1': 9, 'P2': 2, 'P3': 3, 'P4': 4, 'P5': 5}def replace_with_upper(formula_info):    dict_number_info = {"abs": "ABS", "max": "MAX", "min": "MIN"}    for ky in dict_number_info:        val = str(dict_number_info[ky])        formula_info = formula_info.replace(ky, val)    return formula_infodef replace_with_lower(formula_info):    dict_number_info = {"ABS": "abs", "MAX": "max", "MIN": "min"}    for ky in dict_number_info:        val = str(dict_number_info[ky])        formula_info = formula_info.replace(ky, val)    return formula_infodef replace_with_dict(formula_info, dict_number_info):    for ky in dict_number_info:        val = str(dict_number_info[ky])        formula_info = formula_info.replace(ky, val)    return formula_infodef get_max(dict_input):    # 已知条件    formula_info = 'max(a,b,c,d,e)'    dict_map = {'a': 'P1', 'b': 'P2', 'c': 'P3', 'd': 'P4', 'e': 'P5'}    # 第1步：替换关键函数，因为除关键函数的因变量中含有与max等相同的字母    formula_info_1 = replace_with_upper(formula_info)    print('formula_info_1=', formula_info_1)    # 第2步：替换各变量    formula_info_2 = replace_with_dict(formula_info_1, dict_map)    print('formula_info_2=', formula_info_2)    # 第3步：替换回关键函数    formula_info_3 = replace_with_lower(formula_info_2)    print('formula_info_3=', formula_info_3)    # 第4步：替换值    formula_info_4 = replace_with_dict(formula_info_3, dict_input)    print('formula_info_4=', formula_info_4)    result = eval(formula_info_4)    return result# 计算1print('\n', '计算1')result_1 = get_max(dict_input_1)print('结果是', result_1)# 计算2print('\n', '计算2')result_2 = get_max(dict_input_2)print('结果是', result_2)# 计算3print('\n', '计算3')result_3 = get_max(dict_input_3)print('结果是', result_3)</code>