js左移python实现

def correct_shift_v2(ac, n):
	if ac >= 0:
		flag = False
		ac = bin(ac << n).lstrip("0b")[-32:].zfill(32)
	else:
		flag = True
		ac = bin(ac << n).lstrip("-0b")[-32:].zfill(32)
	if ac[0] == "1":#JavaScript这种情况会溢出成为负数
		#翻转替换末尾的0以及挨着的1
		temp = "1" + re.findall("(.*?)1",ac[::-1])[0]
		ac = ac.replace(temp, "")
		ac = list(ac)
		for i, c in enumerate(ac):#取反
			if c == "1":
				ac[i] = "0"
			elif c == "0":
				ac[i] = "1"
			else:
				pass
		ac = "".join(ac) + temp
		ac = -int(ac ,2)
	else:
		ac = int(ac ,2)
	if flag == True:
		ac = -ac
	else:
		pass
	return ac