python ---- 字符串

python ---- 字符串

#字符串截取

#s = "hqelloASd"
#print(s[0:3])
#print(s[:])
#print(s[::2])

#去空格(去左右空格)

#print(s.strip())
#print(s.lstrip())
#print(s.rstrip())

#字符串复制

#s_copy = s
#print(id(s))
#print(id(s_copy))
#s = s.title()
#print(s)
#print(s_copy)
#print(id(s))
#print(id(s_copy))
#s_copy = s[0:2]
#print(id(s))
#print(id(s_copy))

#字符串连接

#s1 = "hpython"
#s2 = s + s1
#print(s2)



import operator
#s2 = operator.concat(s,s1)
#print(s2)


#lt(a, b) ———— 小于
#le(a, b) ———— 小于等于
#eq(a, b) ———— 等于
#ne(a, b) ———— 不等于
#ge(a, b) ———— 大于等于
#gt(a, b) ———— 大于
#b = operator.lt(s,s1)
#print(b)
#print(s<s1)

#字符串长度

#print(len(s),len(s1))

#字符串中最大字符，最小字符

#print(max(s))
#print(min(s1))

#字符串大小写转换

#upper ———— 转换为大写
#lower ———— 转换为小写
#title ———— 转换为标题（每个单词首字母大写）
#capitalize ———— 首字母大写
#swapcase ———— 大写变小写，小写变大写
s = "hqelloASd how are you"
print(s.upper())
print(s.lower())
print(s.title())
print(s.capitalize())
print(s.swapcase())

字符串分割

#s = "hqelloASd how are you"
#ss = s.split("o")
#print(ss)

#字符串连接

#s = "hqelloASd how are you"
#s1 = "ghjkl"
#s2 = s.join(s1)
#print(s2)


a = ['hello','world']
str = "-"
print(str.join(a))

#字符串内查找find

#s1 = 'today is a fine day is'
#index = s1.find("is")
#print(index)

#字符串内替换

s1 = 'todayis a fine day is is is is'
s = s1.replace("is","are",50)
print(s,s1)

#字符串判断

#isdigit ———— 检测字符串时候只由数字组成
#isalnum ———— 检测字符串是否只由数字和字母组成
#isalpha ———— 检测字符串是否只由字母组成
#islower ———— 检测字符串是否只含有小写字母
#isupper ———— 检测字符串是否只含有大写字母
#isspace ———— 检测字符串是否只含有空格
#istitle ———— 检测字符串是否是标题（每个单词首字母大写）
#s = "   d   "
#print(s.isspace())

s = “”"

Variables are used to store information to be referenced and manipulated in a computer program.
They also provide a way of labeling data with a descriptive name, so our programs can be understood
more clearly by the reader and ourselves. It is helpful to think of variables as containers that
hold information. Their sole purpose is to label and store data in memory. This data can then be
used throughout your program.
“”"
#取出所有to

c = s.find("to")
while c!=-1:
    print(s[c:c+2])
    c = s.find("to",c+2)