day10，11-Python 基本数据类型介绍之数字与字符串（看看就好）

数字：int

#字符串转换整型
a = "123"
print(type(a),a)
b = int(a)
print(type(b),b)
b = b + 1000
print(b)

字符串：str

首字母大写：capitalize()

test = "charon"
v =test.capitalize()
print(v)

所有变小写lower()

test = "chAron"
v1 = test.lower()
print(v1)

设置宽度，并将内容居中，20代表总长度。*代表空白位置填充，一个字符可有可无

test = "charon"
v2 = test.center(20,"*")
print(v2)

去字符串中寻找，寻找子序列出现的次数。可以定义起始位置 跟终止位置

test = "charoncccc"
v3 = test.count("c")
print(v3)

以什么开头或者结尾startswith(),endswith()

test = "charon"
v4 = test.startswith("ch")
print(v4)
#返回True
v5 = test.endswith("ch")
print(v5)
#返回False

格式化，将一个字符串中得占位符替换为指定的值format()

test = "i am {name},age {a}"
v5 = test.format(name = "charon",a = 19)
print(v5)

高级点：

test = "i am {0},age {1}"
#占位符0，1，2，3......
v5 = test.format("charon",19)
print(v5)

另一种格式化，跟上面相同。利用字典格式format_map（）

test = "i am {name},age {a}"
v5 = test.format(name = "charon",a = 19)
v6 = test.format_map({"name":"pluto","a":20})
print(v5)
print(v6)

判断字符串中是否只含有数字和字母isalnum()

test = "charon123456"
v7 = test.isalnum()
print(v7)
#如果真返回True，假如含有符号便返回False

判断字符串是否只含字母islpha()

test = "charon123456"
v8 = test.isalpha()
print(v8)
#真返回True,假返回False

判断字符串是否为数字 isdigit()

test = "123456"
v9 = test.isdigit()
print(v9)
#真返回True，假返回False

判断是否是标题istitle()，title()

test = "Return True if all cased characters in S are uppercase and there is"
#判断是否为标题
v10 = test.istitle()
print(v10)
#转化为标题
v11 = test.title()
print(v11)
#再次判断是否为标题
v12 = v11.istitle()
print(v12)

结果：
/ecapp/python3.6/bin/python3.6 /opt/day10/s1.py
False
Return True If All Cased Characters In S Are Uppercase And There Is
True

Process finished with exit code 0

♥将字符串的每一个元素按照指定分隔符进行拼接

test = "iamcharom"
v13 = "-".join(test)
print(v13)

结果：
i-a-m-c-h-a-r-o-m

设置宽度，并将内容居最左，右。20代表总长度，*代表空白位置填充ljust()，rjust()

test = "charom"
v14 = test.ljust(20,"*")
v15 = test.rjust(20,"*")
print(v14)
print(v15)

结果：
charom**************
**************charom

判断是否全部为小写，大写和转换（有点像验证码）

test = "Charom"
v16 = test.islower()
#判断是否为小写
v17 = test.lower()
#转换为小写
print(v16,v17)
v18 = v17.islower()
#再次判断是否为小写
print(v18)
v19 = test.isupper()
#判断是否为大写
v20 = test.upper()
#转换成大写
print(v19,v20)
v21 = v20.isupper()
#再次判断是否为大写
print(v21)

结果：
False charom
True
False CHAROM
True

默认去除左右空白、\n、\t

test = "   charom\t"
v22 = test.lstrip()
print(v22)
v23 = test.rstrip()
print(v23)
v24 = test.strip()
print(v24)

结果：
charom
   charom
charom

分割

test = "charonchaoronaxzc"
v25 = test.partition("a")
v26 = test.rpartition("a")
v27 = test.split("a")
v28 = test.split("a",1)
v29 = test.rsplit("a",1)

print(v25)
print(v26)
print(v27)
print(v28)
print(v29)

结果：
('ch', 'a', 'ronchaoronaxzc')
('charonchaoron', 'a', 'xzc')
['ch', 'ronch', 'oron', 'xzc']
['ch', 'ronchaoronaxzc']
['charonchaoron', 'xzc']

替换

test = "charoncharoncharon"
v30 =  test.replace("ch","bbb")
v31 = test.replace("ch","bbb",1)
v32 = test.replace("ch","bbb",2)

print(v30)
print(v31)
print(v32)

结果:
bbbaronbbbaronbbbaron
bbbaroncharoncharon
bbbaronbbbaroncharon

六个基本会的

join,split,strip,upper,lower,replace

**********************************************************

索引，下标，获取字符串中得某一个字符

test = "charon"
v = test[2]
v1 = test[0:2]
#>=0 <2(下标)
v2 = test[0:-1]
v3 = len(test)
print(v)
print(v1)
print(v2)
print(v3)

结果：
a
ch
charo
6

test = "charon"
index = 0
while index < len(test):
    print(test[index])
    index += 1
print("=======")

range    range(1,100,5)

v = range(100)
for item in v:
    print(item)

test = input(">>>:")
for item in range(0,len(test)):
    print(item,test[item])

　　

四个基本会的　　

for。len。索引。切片，range

深灰魔法

字符串一旦创建就不可修改