AppleScript:字符串中子字符串的索引

Question

我想创建一个函数,该函数从所述字符串的开头返回特定字符串的子字符串,但不包括另一个特定字符串的开头.想法？

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所以类似于:

substrUpTo(theStr, subStr)

因此,如果我输入substrUpTo("Today is my birthday", "my"),它将返回第一个参数的子字符串,但不包括第二个参数开始的位置.(即它会返回"Today is ")

Answer 1

set s to "Today is my birthday"
set AppleScript's text item delimiters to "my"
text item 1 of s
--> "Today is "

Answer 2

内置offset命令应执行以下操作：

set s to "Today is my birthday"
log text 1 thru ((offset of "my" in s) - 1) of s
--> "Today is "