python--字符串

#字符串支持索引访问，是有序的，可迭代的。
#join 连接,参数是一个可迭代类型，而且必须是字符型的
str1 = "a good day"
str2 = ['this','is','good']
print('*'.join(str1))
print('*'.join(str2))
​
a* *g*o*o*d* *d*a*y
this*is*good
#字符串分割
# split(sep=None, maxsplit=-1) -> list of strings. sep:分隔符，默认是空白字符串。maxsplit是分割次数
string = "good 1 good 1 study 2 yes"
print(string.split('1',1))
# rsplit(sep=None, maxsplit=-1) -> list of strings
print(string.rsplit('1',1))
​
# splitlines([keepends]) -> list of strings 行分隔符
string = "good \n day"
print(string.splitlines())
​
# partition(sep) -> (head, sep, tail) 一刀两段，返回头，分隔符，尾，如果没有找到分隔符，
# 返回头，2个空元素的三元组
string = "good 1 good 1 study 2 yes"
print(string.partition('1'))
# rpartition(sep) -> (head, sep, tail) 一刀两段，返回头，分隔符，尾，如果没有找到分隔符，
# 返2个空元素和尾的三元组
string = "good 1 good 1 study 2 yes"
print(string.partition('1'))
print(string.partition('3'))
print(string.partition('1'))
print(string.partition('3'))
['good ', ' good 1 study 2 yes']
['good 1 good ', ' study 2 yes']
['good ', ' day']
('good ', '1', ' good 1 study 2 yes')
('good ', '1', ' good 1 study 2 yes')
('good 1 good 1 study 2 yes', '', '')
('good ', '1', ' good 1 study 2 yes')
('good 1 good 1 study 2 yes', '', '')
# 字符串大小写
string ='ABCedf'
print(string.upper())
print(string.lower())
ABCEDF
abcedf
可以指定替换的次数
# replace(old, new[, count]) -> str count 可以指定替换的次数
print('bag'.replace('a','o'))
bog
ss = 'i am fine'
# strip([chars]) -> str 两端都去除
s = '\t good \r'
ss = 'i am fine'
print(s.strip())
print(ss.strip('iae'))
print(ss.rstrip('iae')) # 除右端的
print(ss.lstrip('iae')) # 除左端的
good
 am fin
i am fin
 am fine
# find(sub[, start[, end]]) -> int 找到返回索引，没有找到返回-1
# rfind(sub[, start[, end]]) -> int  从右到左
ss = 'i am fine am'
print(ss.find('am'))
print(ss.rfind('am'))
2
10
ss = 'i am fine am'
print(ss.index('am'))
# index(sub[, start[, end]]) -> int 找到返回索引，找不到抛错
# rindex(sub[, start[, end]]) -> int
ss = 'i am fine am'
print(ss.index('am'))
print(ss.rindex('am'))
2
10

ss = 'i am fine am'
print(ss.count('am'))
# count(sub[, start[, end]]) -> int 统计出现的次数
​
ss = 'i am fine am'
print(ss.count('am'))
2
ss = 'i am fine am'
# endswith(suffix[, start[, end]]) -> bool
# startswith(prefix[, start[, end]]) -> bool
​
ss = 'i am fine am'
print(ss.endswith('am'))
print(ss.startswith('am'))
True
False
# 字符串判断is
ss = 'i am fine am'
print(ss.isalnum())
print(ss.isalpha())
print(ss.isdecimal())
print(ss.isdigit())
print(ss.isidentifier())
print(ss.islower())
print(ss.isupper())
print(ss.isspace())
​
False
False
False
False
False
True
False
False