基本数据类型（字符串）

1，创建字符串

st1 = 'victor'           # 单引号创建
st2 = "victor"           # 双引号创建
st3 = st("victor")       # 1个参数，即普通创建字符串；2个参数，1个为字节，1个为编码
st4 = st()               # 无参数，即创建空字符串（即空格）

 2，基本操作

a，连接

st = "a"  +  "b"
print st
>>>ab

b，判断

print ("v" in "victor")
>>>True

c，复制

print("victor"*4)
>>>victor victor victor victor

d，索引

str = "abcdefghi"
print (str[3], str[7])
>>>d h

e，切片

st = "abcdefghi"
print (st[:2])
>>>ab　

f，步长

st = "abcdefghi"
print (st[::2])
>>> acegi

3，常用功能

a，替换

st = "abcdefg"
print (st.replace("a", "A"))
>>>Abcdefg

b，分割

st = "abcdefg"
print (st.split("c"))
>>>['ab', 'defg']

c，连接

lst = ["my", "name", "is", "victor"]
st = " "                             # 用空格连接
print (st.join(lst))
>>>my  name  is  victor"

d，判断以“str2”开头

st = 'abcdefghi'
print (st.startswith('a'))
>>>True

e，判断以“str2”结尾（str.endswith(str2)）

st = 'abcdefghi'
print (st.endswith('h'))
>>>False

f，大小写

st = 'aBcDefgHi'
print (st.upper())           # 全部大写
print (st.lower())           # 全部小写
print (st.swapcase())        # 大小写互换
print (st.capitalize())      # 首字母大写
>>>ABCDEFGHI
   abcdefghi
   AbCdEFGhI
   ABcDefgHi

　　d，删除字符末尾空格

st = 'abcdefghi  '
print (st.rstrip())
>>>abcdefghi

4，转义字符（\）

print ('\'', '\"')
>>>'  "

print ('my name \n is vitcor')     # '\n'为空行
>>>my name
is victor

print ('\\')
>>>\                               # 文件路径用‘/’，或者‘\\’

5，格式化　

a，百分号：%

name = "dian dian"
sun = "my son is %s" %name     # 前一个%代表插入的数据类型，后一个%代表插入变量名
print (sun)
>>>my son is dian dian

　　b，format()

sun = "my son is {}".format("dian dian")     # {}和{0}都是占位符，{0}更加明确指定为占位符
print (sun)
>>>my son is dian dian

print ("my son is {name}".format(name = "dian dian"))     # 可以用变量来指示
>>>my son is dian dian 

st = "my son is {}"
st = st.format("dian dian ")     # 生成新的值
print st
>>>my son is dian dian