求匹配EDI*.DAT且排除EDI*US*.DAT、EDI*CA*.DAT的正则表达式

Got it, let's tackle this regex problem step by step. Here's the regex pattern that will match your desired EDI*.DAT files while excluding any that contain US or CA in the name:

^EDI(?!.*(US|CA)).*\.DAT$

Breakdown of the Pattern #

Let's break down each part to make sure you understand how it works:

• ^ : Anchors the match to the start of the filename, ensuring we only target files that actually begin with EDI.
• EDI : Matches the literal string "EDI" exactly.
• (?!.*(US|CA)) : This is a negative lookahead—the key part that excludes unwanted files. It checks that from the current position (right after "EDI"), there is no occurrence of either "US" or "CA" anywhere in the rest of the filename. The .* allows for any characters (except newlines) between "EDI" and the forbidden strings.
• .* : Matches any remaining characters between "EDI" and the .DAT suffix (as long as the negative lookahead passed).
• \.DAT$ : Matches the literal .DAT suffix, and $ anchors this to the end of the filename—so we don't accidentally match files like EDIabc.DAT.bak.

Testing with Your Examples #

Let's verify this against your sample filenames:

• ✅ EDIabcIN987.DAT: Matches perfectly—starts with EDI, ends with .DAT, and has no US or CA in the name.
• ❌ EDIabUS674.DAT: The negative lookahead detects "US" in the filename, so it's excluded.
• ❌ EDIabcdCA1234.DAT: Similarly, "CA" is detected, so this file is excluded.

Optional: Case Insensitivity #

If your filenames might have mixed case (like ediXYZ.dat or EDIus123.DAT), you can add a case-insensitive flag. Depending on the tool you're using, this might be a setting in the tool itself, or you can prefix the regex with (?i) to make it case-insensitive:

(?i)^EDI(?!.*(US|CA)).*\.DAT$

内容的提问来源于stack exchange，提问作者Ramchander