python字符串

字符串中的方法：

#首先写两个字符串如下：
S="fdsfdsjkds.com"
S1="HHHJJKGGYVCJ"
#1、首字母大写
print("1:",S.capitalize())

#2、计数
print("2:",S.count("f"))

#3、整个字符串大写变小写
print("3:",S1.casefold())

#4、格式化居中操作
print("4:",S.center(50,"*"))

#5、格式转换
# S.encode(encoding="utf-8")
# S.encode(encoding="GBK")
# print(S.encode(encoding="utf-8"))

#6、判断以"??"结尾
print("6:",S.endswith(".jpg"))

#7、查找某一个字符第一次在字符串中的出现的位置
print("7:",S.find("f"))

#8.1格式化操作
# name="{name} is {age}"
# print(name)
# print(name.format(name="feng",age=19))
#8.2
name="{name} is {age}"
print("8.2:",name.format_map({"name":"feng1","age":"20"}))
#8.3
#该字符串操作，填入的参数是元组
# print("%s is " % "feng")
# print("%s is " % ("feng"))
# print("%s is %s" % ("feng",73821))
# print("%s is %d" % ("feng",73821))
# print("%s is %d" % "feng",73821)     #默认追加一个参数
# print("%s is %d" % ("feng","jfdks"))   #错误

#9、判断是否由数字组成
S="342"
print("9:",S.isalnum())

#10、判断是否由字母组成(包含大小写)
S="fdsfdsjkdscomDDDD"
print("10:",S.isalpha())

#11、判断是否是十进制数
S="73281"
# S="1A"
print("11:",S.isdecimal())

#12、判断是不是整数
S="8493.2"
print("12:",S.isdigit())

#13、判断是不是一个合法的标识符
S="e0__fjdsk"
print("13:",S.isidentifier())

#14、判断是不是小写
S="jfdksSSS"
print("14:",S.islower())

#15、判断是不是数字
S="8989--"
print("15:",S.isnumeric())

#16、判断是不是空格
S="  "
print("16:",S.isspace())

#17、判断字符串中每一个单词是不是大写开头
S="Gfs Adjfkds"
print("17:",S.istitle())

#18、判断字符串能不能打印（用途较少）
S="fjkds"
print("18:",S.isprintable())

#19、判断是不是大写
S="IIOJfdsfdsH"
print("19:",S.isupper())

#20、join格式化
print("20:","+".join(["1","2","3"]))

#21.1、向左格式化打印
S="jfkdlsjfkds"
print("21.1:",S.ljust(30,"+"))

#21.2、向右格式化打印
print("21.2:",S.rjust(30,"+"))

#22、大写变小写
S="JKHJKHJK"
print("22:",S.lower())

#23、小写变大写
S="jfkds"
print("23:",S.upper())

#24.1、去掉左边空格和回车
S="\njfkdsj"
print(S)
print("24:",S.lstrip())

#24.2、去掉右边空格和回车
S="fdks\n"
print(S+"jfkdsl")
print("24.2:",S.rstrip()+"jfkdls")

#24.3、去掉两端全部空格和回车
S="\nfhdsj\t"
print("24.3:",S.strip()+"jfdksncue")

#25、自定义格式化(形成对照表),,,两字符串长度必须一致
p=str.maketrans("1234567","abcdefg")
print("25:","5372".translate(p))

#26、字符串替换
s="bubunimovyisa"
print("26:",s.replace("b","B",3))

运行结果如下：

1: Fdsfdsjkds.com
2: 2
3: hhhjjkggyvcj
4: ******************fdsfdsjkds.com******************
6: False
7: 0
8.2: feng1 is 20
9: True
10: True
11: True
12: False
13: True
14: False
15: False
16: True
17: True
18: True
19: False
20: 1+2+3
21.1: jfkdlsjfkds+++++++++++++++++++
21.2: +++++++++++++++++++jfkdlsjfkds
22: jkhjkhjk
23: JFKDS

jfkdsj
24: jfkdsj
fdks
jfkdsl
24.2: fdksjfkdls
24.3: fhdsjjfdksncue
25: ecgb
26: BuBunimovyisa

Process finished with exit code 0