英文:
Regex to extract a number of any length from a string
问题
我正试图从一个字符串中提取一个数字（必定存在，长度任意）。该字符串实际上应以这个数字开头。我正在使用这个表达式：
[[\d]+YMD]
当输入为11M时，11被匹配两次，分别是1和1。在这个正则表达式中我漏掉了什么？我正在编写一个网页应用，但目前我正在使用在线工具测试这个正则表达式，结果是一样的。
英文:
I am trying to extract a number (Must exist, any length) from a string. The string should actually start with the number. I am using this expression:
[[\d]+YMD]
When given 11M as input, the 11 is matched twice as 1 then 1. What am I missing in this RegEx?
I am writing a web application, but for now, I am testing the RegEx online where I am getting the same results.
答案1
得分: 1
我猜你想要：
^\d+
^ = 字符串的开头
\d = 任意数字
+ = 1个或更多
英文:
I guess you want:
^\d+
^ = start of string
\d = any digit
+ = 1 or more
答案2
得分: 1
你可能最需要的是 + 量词，它的作用是：“匹配一次或多次，尽可能多次地匹配，根据需要回退”。
^\d+(D|M|Y) 将会确切地给你你似乎正在寻找的内容（只有在以数字开头并以 D、M 或 Y 结尾时才匹配，确保至少有一个数字）。
链接：https://regex101.com/r/gWxkhd/2
英文:
You're most likely looking for the + quantifier which: "Matches between one and unlimited times, as many times as possible, giving back as needed".
^\d+(D|M|Y) will specifically give you what you seem to be looking for (making it only match if it starts with a number and ends with D, M, or Y, making sure there's at least 1 number.
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