4. Transform the Expression

Code:

tc = int(raw_input()) 

while tc: 
    q = str(raw_input()) 
    q = list(q) 
       
    stack = [] 
    post = [] 

    stack.append('(') 
    q.append(')') 

    length = len(q) 
     
    i = 0 
    while i < length: 
        if q[i] == '(': 
            stack.append(q[i]) 

        elif q[i] == ')': 
            while 1 and len(stack) != 0: 
                temp = stack.pop() 
                if temp == '(': 
                    break 
                else: 
                    post.append(temp) 
     
        elif q[i] == '+' or q[i] == '-' or q[i] == '*' or q[i] == '/' or q[i] == '^': 
            if q[i] == '^': 
                stack.append(q[i]) 
            elif q[i] == '*' or q[i] == '/': 
                while 1 and len(stack) != 0: 
                    temp = stack.pop() 
                    if temp == '^' or temp == '*' or temp == '/': 
                        post.append(temp) 
                    else: 
                        stack.append(temp) 
                        stack.append(q[i]) 
                        break 

            elif q[i] == '+' or q[i] == '-': 
                while 1 and len(stack) != 0: 
                    temp = stack.pop() 
                    if temp == '^' or temp == '*' or temp == '/' or temp == '+' or temp == '-': 
                        post.append(temp) 
                    else: 
                        stack.append(temp) 
                        stack.append(q[i]) 
                        break     

        elif q[i] >= 'a' and q[i] <= 'z': 
            post.append(q[i]) 
     
        i = i + 1 
     
    tc = tc - 1 
    print "".join(post)

Be Pythonic