c -string ab Result: True ...

Question

is a

Namespace

python regex.py -nfa a.b|c -string ab
Result: True

object, not a

dictionary

.

You should access the args provided as properties:

    parser = argparse.ArgumentParser(add_help=False)
    parser.add_argument("-nfa", required=True, help="NFA",type=str)
    parser.add_argument("-string", required=True, help="String to match to nfa",type=str)
    parser.add_argument('-h', '--help', action='help', default=argparse.SUPPRESS, help='Default Help Message of Project Command line')
    args = parser.parse_args()
    print(" Result:", match(str(args['nfa']), str(args['string'])))

So change:

def match(regex, s):
    """Match a string to an NFA"""
    #this function will return true if and only if the regular expression
    #regex (fully) matches the string s. It returns false otherwise

    #compile the regular expression into nfa
    nfa = compile(regex)

    # try to match the regular expression to the string s.
    #the current set of states
    current = set()
    #add the first state, and follow all of epsilon arrows
    followEs(nfa.start, current)
    #the previuos set of states
    previous = set()
    #loop through characters in s
    for c in s:
        previous = current
        #creat a new empty set for states we're about to be in
        current = set()
        #loop through the previous states
        for state in previous:
            #only follow arrows not labeled by E (epsilon)
            if state.label is not None:
                #if the label of the state is = to the character we've read
                if state.label == c:
                    #add the state(s) at the end of the arrow to current.
                   followEs(state.edges[0], current)
    #ask the nfa if it matches the string s.
    return nfa.accept in current    

to:

def compile(infix):
    """Return Fragment of NFA that represents infix regex"""
    #convert infix to postfix
    postfix = shunting.shunt(infix)
    #make a listfix stack of chars and invert it
    postfix=list(postfix)[::-1] 
    #stack for nfa fragments
    nfa_stack = []
    while(postfix):
        #pop character from postfix
        c= postfix.pop()
        if(c=='.'):#pop two frags off stack
            frag1=nfa_stack.pop()
            frag2=nfa_stack.pop()
            #point from end of frag2 to start of frag1
            frag2.accept.edges.append(frag1.start)
            #frag2's start state is new start state
            start = frag2.start
            #frag1s new accept state 
            accept = frag1.accept
        elif(c=='|' ):
            #pop 2 frags off stack
            frag1=nfa_stack.pop()
            frag2=nfa_stack.pop()
            #create new start and accept states
            accept = State()
            start= State(edges=[frag2.start,frag1.start])
            #point old accept states at new one
            frag2.accept.edges.append(accept)
            frag1.accept.edges.append(accept)
        elif(c=='*'):
            #pop single fragment off stack
             frag= nfa_stack.pop()
             #create new start and accept state
             accept = State()
             #point arrows i
             start= State(edges=[frag.start,accept])
             frag.accept.edges=[frag.start,accept]     
        else:
            accept = State()
            start = State(label=c,edges=[accept])
        #create new instance of fragment to represent the new nfa
        newfrag = Fragment(start,accept)
        #push new nfa to stack
        nfa_stack.append(newfrag)
    #the nfa stack should have exactly one nfa one it -  the answer
    return nfa_stack.pop()

If you want to convert

Answer 1

args编写一个脚本来匹配一个字符串输入到一个非确定性有限自动机，我想能够从命令行中接收字符串，如 但是当我尝试这样做的时候，我得到了错误 回溯（最近一次调用）。 文件 "regex.py", 第144行, in print(" Result:", format(match(str(args['nfa']), str(args['string']))) 类型错误：'Namespace'对象不可下标。发生错误的代码在这里。

Match(): args.arg1, args.arg2, etc..

编译():

print(" Result:", match(str(args['nfa']), str(args['string'])))

print(" Result:", match(str(args.nfa), str(args.string)))

args我正在编写一个脚本来匹配一个字符串输入到一个非确定性有限自动机上 我希望能够从命令行中获取字符串，例如： python regex.py -nfa a.b