1 #!/usr/bin/env python
  2 # -*- coding:utf8 -*-
  3
  4 #测试并记录str数据类型的各个方法
  5
  6 str1 = "root"
  7 #收字母大写
  8 v1 = str1.capitalize()
  9 print(v1)
 10
 11 str2 = "RooT"
 12 #字符串转为小写 推荐使用 会将各国的字符都变为小写
 13 v2 = str2.casefold()
 14 print(v2)
 15 #只可将常规的英文大写字符变为小写
 16 v2 = str2.lower()
 17 print(v2)
 18
 19 #转换后的字符串占多少位，且原字符串在中间，左右以 * 填充 也可不写，若不写 默认为空格
 20 # 若设置位数小于源字符串位数，则显示原字符串
 21 #若位数无法平分，多出的填充字符放置在原字符串右边
 22 v3 = str2.center(10, "*")
 23 print(v3)
 24
 25 str3 = "pythonpy"
 26 #在当前字符串中查询子序列出现的次数,可指定在起止位置查找出现的次数
 27 v3 = str3.count("py")
 28 print(v3)
 29 v3 = str3.count("py", 0, 4)
 30 print(v3)
 31
 32 #是否为某个字符串结尾,可指定某一段字符串
 33 v3 = str3.endswith("py")
 34 print(v3)
 35 v3 = str3.endswith("h", 0, 4)
 36 print(v3)
 37
 38 #将#TAB替换为几个空格 包含#TAB前面的字符
 39 str4 = "aaaaa\t9"
 40 print(str4)
 41 v4 = str4.expandtabs(20)
 42 print(v4)
 43
 44 #找字符串首次出现的位置,若没有 则返回-1, 同时可以指定在固定位置查找   推荐使用
 45 str5 = "pythonpy"
 46 v5 = str5.find("th")
 47 print(v5)
 48 v5 = str5.find("the")
 49 print(v5)
 50
 51 v5 = str5.find("py", 3)
 52 print(v5)
 53
 54 #字符串格式化
 55 str6 = "i am {name}, age {age}"
 56 print(str6)
 57 v6 = str6.format(name="Jack", age=18)
 58 print(v6)
 59 str6 = "i am {0}, age {1}"
 60 v6 = str6.format("Lucy", 16)
 61 print(v6)
 62 #以map格式的字符串格式化
 63 str6 = "i am {name}, age {age}"
 64 v6 = str6.format_map({"name":"Tom","age":20})
 65 print(v6)
 66
 67
 68 """
 69     首次出现的位置，若没有则报错,同时可以指定在固定字符串范围内查找 和 find比较 推荐使用find
 70     Traceback (most recent call last):
 71       File "D:/Python_Study/day02/str.py", line 69, in <module>
 72         v7 = str7.index("one")
 73     ValueError: substring not found
 74 """
 75 str7 = "pythonpy"
 76 v7 = str7.index("py")
 77 print(v7)
 78 v7 = str7.index("py", 3)
 79 print(v7)
 80
 81 #字符串是否只包含字符和数字，若是则返回True 否则False
 82 str7 = "abc123"
 83 v7 = str7.isalnum()
 84 print(v7)
 85 str7 = "abc123_"
 86 v7 = str7.isalnum()
 87 print(v7)
 88
 89 #字符串是否只包含字符，若是则返回True 否则False
 90 v7 = str7.isalpha()
 91 print(v7)
 92 str7 = "abc"
 93 v7 = str7.isalpha()
 94 print(v7)
 95
 96 #字符串是否是ascii码 是返回True  否则False
 97 v7 = str7.isascii()
 98 print(v7)
 99 str7 = "中国"
100 v7 = str7.isascii()
101 print(v7)
102
103 #字符串是一个十进制的整数 返回True 否则返回False
104 str8 = "101"
105 v8 = str8.isdecimal()
106 print(v8)
107
108 #字符串是一个数字返回True 否则返回False
109 str9 = "01010"
110 v9 = str9.isdigit()
111 print(v9)
112
113 #字符串是否是python的有效命名方式 是返回True 否则返回False
114 str10 = "sum_10"
115 v10 = str10.isidentifier()
116 print(v10)
117 str10 = "10_sum"
118 v10 = str10.isidentifier()
119 print(v10)
120
121 #是否是数字 是True 否False
122 str11 = "11"
123 v11 = str11.isnumeric()
124 print(v11)
125
126 #是否可打印
127 str12 = ""
128 v12 = str12.isprintable()
129 print(v12)
130
131 #字符串是否为空格 包含转义空格 #TAB等
132 str13 = "\t"
133 v13 = str13.isspace()
134 print(v13)
135
136 #是否可为标题 各个单词首字母大写 是True 否False
137 str14 = "Is Is"
138 v14 = str14.istitle()
139 print(v14)
140 str14 = "Is is"
141 v14 = str14.istitle()
142 print(v14)
143
144 #字符串英文字符是否为大写
145 str15 = "A123中"
146 v15 = str15.isupper()
147 print(v15)
148
149 #以当前字符串为连接符将join中的字符串连接起来
150 str16 = "python"
151 v16 = str16.join(["A", "B", "C", "D", "Ee"])
152 print(v16)
153
154 #左对齐 以设置的字符填充到设置长度的字符串
155 str17 = "python"
156 v17 = str17.ljust(15, "P")
157 print(v17)
158
159 #去除字符串左边的空格
160 str18 = "  p ython  "
161 v18 = str18.lstrip()
162 print(v18)
163
164 # str19 = "python"
165 # v19 = str19.maketrans()
166 # print(v19)