如何检查是否在 Lua 的字符串中找到匹配的文本? [英] How to check if matching text is found in a string in Lua?

问题描述

如果在文本字符串中至少找到一次特定匹配文本，我需要创建一个条件为真，例如:

str = "这是一些包含老虎这个词的文本."如果 string.match(str, "tiger") 然后打印(老虎这个词被发现了.")别的打印(没有找到老虎这个词.")

如何检查是否在字符串中的某处找到文本?

解决方案

有 2 个选项可以找到匹配的文本；string.match 或 string.find.

两者都对字符串执行正则表达式搜索以查找匹配项.

---

string.find()

string.find(主题字符串，模式字符串，可选的起始位置，可选的普通标志)

返回 startIndex &找到的子串的endIndex.

plain 标志允许忽略模式，而是将其解释为文字.不是将 (tiger) 解释为与 tiger 匹配的正则表达式捕获组，而是在字符串中查找 (tiger).>

反过来说，如果你想要正则表达式匹配但仍然想要文字特殊字符(例如 .()[]+- 等)，你可以用百分比对它们进行转义；%(tiger%).

您可能会将它与 string.sub

结合使用

示例

str = 这是一些包含老虎这个词的文本.";如果 string.find(str, "tiger") 然后打印(找到了老虎这个词.")别的打印(没有找到老虎这个词.")结尾

---

string.match()

string.match(s, 模式, 可选索引)

返回找到的捕获组.

示例

str = 这是一些包含老虎这个词的文本.";如果 string.match(str, "tiger") 然后打印(找到了老虎这个词.")别的打印(没有找到老虎这个词.")结尾

I need to make a conditional that is true if a particular matching text is found at least once in a string of text, e.g.:

str = "This is some text containing the word tiger."
if string.match(str, "tiger") then
    print ("The word tiger was found.")
else
    print ("The word tiger was not found.")

How can I check if the text is found somewhere in the string?

解决方案

There are 2 options to find matching text; string.match or string.find.

Both of these perform a regex search on the string to find matches.

---

string.find()

string.find(subject string, pattern string, optional start position, optional plain flag)

Returns the startIndex & endIndex of the substring found.

The plain flag allows for the pattern to be ignored and intead be interpreted as a literal. Rather than (tiger) being interpreted as a regex capture group matching for tiger, it instead looks for (tiger) within a string.

Going the other way, if you want to regex match but still want literal special characters (such as .()[]+- etc.), you can escape them with a percentage; %(tiger%).

You will likely use this in combination with string.sub

Example

str = "This is some text containing the word tiger."
if string.find(str, "tiger") then
  print ("The word tiger was found.")
else
  print ("The word tiger was not found.")
end

---

string.match()

string.match(s, pattern, optional index)

Returns the capture groups found.

Example

str = "This is some text containing the word tiger."
if string.match(str, "tiger") then
  print ("The word tiger was found.")
else
  print ("The word tiger was not found.")
end

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