for circulation and hex conversion

for loop

1. The basic structure of a for loop

   for+空格+in+可迭代对象+冒号(#整型和布尔值不能进行循环)
   缩进   循环体
   for i in 'asdf':#i是变量名
       pass#pass和...是占位符
   print(i)#当在外围打印i时,值应该是for循环变量最后所获得的值

2. Examples

   name="你好啊"
   for x in name:#将name中的字符循环依次赋值给x
      print(x)
   #结果为 
   #你
   #好
   #啊
   count=0#因为字符串的元素索引第一个是0，所以count赋值为0
   while count<len(name)#获取name字符串的长度进行判断
      print(name[count])#依次输出name中索引的值
       count+=
       #结果为：
       #你
       #好
       #啊

3. The for loop is cyclic data structure:

   • String (str)
   • List (list)
   • Tuples (tuple)
   • Dictionary (dict)
   • Collection (set)

   Alone can not circulate is integer (int) and boolean value (bool)

Hexadecimal conversion

--- Digital integer (int)

• For comparison and arithmetic

• 32-bit range of -2 31 to 2 ** 32-1 **

• Range of -2 ** 64 ** 63-1 63-2

• Decimal Binary transfer calculation:

• 15的二进制为
  15%2=7...1
  7%2=3....1
  3%2=1....1
  1%2=0....1
  最后结果为1111  

• Converting into binary integer

• print(bin(186)) 

• Binary Coded Decimal Calculation Method:

• 1111转十进制
  1*2**0+1*2**1+1*2**2+1*2*3

• Binary Coded Decimal System:

• print(int("1111",2))#2代表是几进制

• bool () Boolean value

• print(bool(1))#非零为True，零为False
  print(bool("123"))#空字符串为Flase,不为空字符串为True

format () format conversion

# 对齐方式:
print(format(122,">20")) 
print(format(122,"<20"))
print(format(122,"^20"))

# 进制转换:
将十进制转换成二进制
print(format(12,"b"))
print(format(12,"08b"))

将十进制转换成八进制
print(format(12,"o"))
print(format(12,"08o"))

将二进制转换成十进制
print(format(0b11001,"d"))

将十进制转换成十六进制
print(format(17,"x"))
print(format(17,"08x"))