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