Python Learning Path-python Basic Course (DAY6)

Homework:

Develop a simple Python calculator

1. Implementation of subtraction and extension priority resolution
2. User Input 1-2 * ((60-30 + ( -40/5) * (9-2*5/3 + 7/3*99/4*2998 +10 * 568/14))-( -4*3)/(16-3*2)) and other similar formulas, you must parse the inside (), +,-, *,/character Number and formula (cannot call Eval and other similar functions lazy implementation), the result of the operation, the results must be consistent with the results of the actual calculator

Calculator Source:

#!/usr/bin/env python#_*_ coding:utf-8 _*_#Author:moImportRedefCompute_multipy_divide (ARG): Value=Arg[0] MCH= Re.search ('\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*', value)if  notMCH:returncontent= Re.search ('\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*', value). Group ()ifLen (Content.split ('*')) > 1: V1,v2= Content.split ('*') Get_value= Float (v1) *Float (v2)Else: V1,v2= Content.split ('/') Get_value= Float (v1)/Float (v2) left,right= Re.split ('\d+\.*\d*[\*\/]+[\+\-]?\d+\.*\d*', value,1) New_value='%s%s%s'%(left,get_value,right) arg[0]=new_value compute_multipy_divide (ARG)defCompute_add_substract (ARG): whileTrue:if '--' inchARG[0]or '++' inchARG[0]or '-+' inchARG[0]or '+-' incharg[0]: arg[0]= Arg[0].replace ('--','+') arg[0]= Arg[0].replace ('++','+') arg[0]= Arg[0].replace ('-+','-') arg[0]= Arg[0].replace ('+-','-')        Else:             Break    ifArg[0].startswith ('-'): arg[1] + = 1Arg[0]= Arg[0].replace ('-','&') arg[0]= Arg[0].replace ('+','-') arg[0]= Arg[0].replace ('&','+') arg[0]= Arg[0][1:] Value=Arg[0] MCH= Re.search ('\d+\.*\d*[\+\-]{1}\d+\.*\d*', value)if  notMCH:returncontent= Re.search ('\d+\.*\d*[\+\-]{1}\d+\.*\d*', value). Group ()ifLen (Content.split ('+')) >1: V1,v2= Content.split ('+') Get_value= Float (v1) +Float (v2)Else: V1,v2= Content.split ('-') Get_value= Float (v1)-Float (v2) left,right= Re.split ('\d+\.*\d*[\+\-]{1}\d+\.*\d*', str (value), 1) New_value='%s%s%s'%(left,get_value,right) arg[0]=new_value compute_add_substract (ARG)defCompute (expression): InP=[expression,0] Compute_multipy_divide (INP) compute_add_substract (INP) Count= Divmod (inp[1],2) Result=float (inp[0])ifCOUNT[1] = = 1: Result= result * (-1)    returnresultdefexcute (expression):if  notRe.search ('\ (([\+\-\*\/]*\d+\.*\d*) {2,}\)', expression): Result=compute (expression)returnresult Content= Re.search ('\ (([\+\-\*\/]*\d+\.*\d*) {2,}\)', expression). Group () New_content= Content[1:len (content)-1] New_list= Re.split ('\ (([\+\-\*\/]*\d+\.*\d*) {2,}\)', expression,1)    Print('before calculation:', expression) left=New_list[0] right= New_list[2] Final=Compute (new_content)Print('calculation:%s=%s'%(new_content, Final)) New_expression='%s%s%s'%(left,final,right)Print('after calculation:', New_expression)Print('end of last calculation'. Center (50,'*'))    returnExcute (new_expression)defrun (): whileTrue:Print('Oldboy Calc'. Center (50,'*')) Str_input= Input ('(quit=q) >>:'). Strip ()ifStr_input = ='Q': Exit ()ifLen (str_input) = = 0:Continue        ifLen (str_input) >0:no_space_str= Re.sub ('\s*',"', Str_input) Final=Excute (NO_SPACE_STR)Print(Final)if __name__=='__main__': Run ()

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Calculation Result:

Oldboy Calc *******************(Quit=Q) >>:1-2 * ((60-30 + ( -40/5) * (9-2*5/3 + 7/3*99/4*2998 +10 * 568/14))-( -4*3)/(16-3*2) ) before calculation:1-2* ((60-30+ ( -40/5) * (9-2*5/3+7/3*99/4*2998+10*568/14))-( -4*3)/(16-3*2) ) Calculation:-40/5=-8.0after calculation:1-2* ((60-30+-8.0* (9-2*5/3+7/3*99/4*2998+10*568/14))-( -4*3)/(16-3*2))Last calculated end **********************before calculation:1-2* ((60-30+-8.0* (9-2*5/3+7/3*99/4*2998+10*568/14))-( -4*3)/(16-3*2) ) Calculation:9-2*5/3+7/3*99/4*2998+10*568/14=173545.88095238098after calculation:1-2* (60-30+-8.0*173545.88095238098)-( -4*3)/(16-3*2))Last calculated end **********************before calculation:1-2* (60-30+-8.0*173545.88095238098)-( -4*3)/(16-3*2) ) Calculation:60-30+-8.0*173545.88095238098=-1388337.0476190478after calculation:1-2* ( -1388337.0476190478-( -4*3)/(16-3*2))Last calculated end **********************before calculation:1-2* ( -1388337.0476190478-( -4*3)/(16-3*2) ) Calculation:-4*3=-12.0after calculation:1-2* ( -1388337.0476190478--12.0/(16-3*2))Last calculated end **********************before calculation:1-2* ( -1388337.0476190478--12.0/(16-3*2) ) Calculation:16-3*2=10.0after calculation:1-2* ( -1388337.0476190478--12.0/10.0)Last calculated end **********************before calculation:1-2* ( -1388337.0476190478--12.0/10.0) Calculation:-1388337.0476190478--12.0/10.0=-1388335.8476190479after calculation:1-2*-1388335.8476190479********************** Last calculated end **********************2776672.6952380957****************** Oldboy Calc *******************(Quit=Q) >>:q

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Python Learning Path-python Basic Course (DAY6)