python 基础数据结构之字符串操作

#切割部分
s = 'I love you more than i can say'
# 切割字符串
# sep：指定按照什么进行切割，默认按照空格切割
# maxsplit：指定最大切割次数，默认不限制次数
# ret = s.split(sep='abc', maxsplit=1)
# 从右边进行切割
ret = s.rsplit(' ', maxsplit=7)#以空格切割
print(ret)
#等价于下面操作
s = 'I love you more than i can say'
ret = s.split()
print(ret)

s = 'Hello\nworld'
# 按照换行进行切割

print(s.splitlines())

s = 'I love you more than i can say'
ret = s.split()
print(ret)
#字符串拼接
s2 = '*'.join(ret)
print(s2)#I*love*you*more*than*i*can*say

#查询操作
s = 'Hi buddy, if you have something to say, than say; if you have nothing to say, than go.'

# 子串查找：找到首次出现的位置，返回下标，找不到返回-1
ret = s.find('hello')
print(ret)#-1
# 从后面查找
ret = s.rfind('to')#70
print(ret)
print(s[70],s[71])#t o
# 统计子串出现的次数
ret = s.count('if')
print(ret)#2

#判断部分
# 判断是否已指定内容开头

s = 'Hi buddy, if you have something to say, than say; if you have nothing to say, than go.'

ret = s.startswith('Hi')
print(ret)#True
# 判断是否已指定内容结尾
ret = s.endswith('go.')
print(ret)#True

s = 'hellO worlD!'
# 转换为全大写
print(s.upper())#HELLO WORLD!
# 转换为全小写
print(s.lower())#hello world!
# 大小写转换
print(s.swapcase())#HELLo WORLd!
# 首字母大写
print(s.capitalize())#Hello world!
# 每个单词首字母大写
print(s.title())#Hello World!
# 用指定的内容替换指定内容，还可以值替换次数
print(s.replace('l', 'L', 2))#heLLO worlD!

s = 'abcABC2'
# 是否是全大写
print(s.isupper())#False
# 是否是全小写
print(s.islower())#False
# 是否每个单词首字母都大写
print(s.istitle())#False
# 是否是全数字字符
print(s.isdecimal())#False
# 是否是全字母
print(s.isalpha())#False
# 是否全是字母或数字
print(s.isalnum())#False