如何在单词之间只允许 3 种类型的字符? [英] How to allow only 3 types of characters between words?

问题描述

我有一组允许的字符:

1. 撇号`

空白区域  

empty space  

破折号 -

我正在努力构建一个正则表达式:

I'm struggling with building a regex which:

一个.每个单词之间只允许出现一次允许的字符(允许任意数量的单词)

a. allows only one occurrence of the allowed characters between each word (any number of words are allowed)

E.g.
text-text    --> VALID
text text    --> VALID
text`text    --> VALID

B.允许允许字符的组合，但不能一个接一个

b. allows combinations of allowed characters but not one after the other

E.g.
text-text`text    --> VALID
text text-text    --> VALID
text`text text    --> VALID
text``text  text  --> INVALID
text`text  text   --> INVALID
text`text -text   --> INVALID

c.不允许以空格 撇号` 或破折号 - 开头，也不允许以撇号 ` 或破折号 - 结尾，但可以以[空格]结束

c. doesn't allow to start with empty space apostrophe ` or dash - and doesn't allow to end with apostrophe ` or dash - but can end with [emptyspace]

E.g.
text[emptyspace]  --> VALID
[emptyspace]text  --> INVALID
`text             --> INVALID
text`             --> INVALID
-text             --> INVALID
text-             --> INVALID

d.完全不允许特殊字符

d. Special characters are not allowed at all

e.完全不允许数字

这是我到目前为止所拥有的:https://regex101.com/r/9i3vq2/5

This is what I have so far: https://regex101.com/r/9i3vq2/5

推荐答案

您可以使用

^[a-zA-Z]+(?:[ `-][a-zA-Z]+)* ?$

查看正则表达式演示

详情

• ^ - 字符串的开始
• [a-zA-Z]+ - 1+ 个 ASCII 字母
• (?:[ `-][a-zA-Z]+)* - 0 次或多次重复
  • [ `-] - 空格、反引号或 -
  • [a-zA-Z]+ - 1+ 个 ASCII 字母
  • ^ - start of string
  • [a-zA-Z]+ - 1+ ASCII letters
  • (?:[ `-][a-zA-Z]+)* - 0 or more repetitions of
    • [ `-] - a space, backtick or -
    • [a-zA-Z]+ - 1+ ASCII letters

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