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"删除每行除前四个字符之外的所有字符"

[英]Remove all but the first four characters on each line

原文 2022-02-06 20:59:38 5 2 regex/ visual-studio-code

So I have a text file in Vscode that contains several lines of text like so:所以我在 Vscode 中有一个文本文件，其中包含几行文本，如下所示：

1801: Joseph Marie Jacquard, a French merchant and inventor invent a loom that uses punched wooden cards to automatically weave fabric designs. Early computers would use similar punch cards.

So now I'm trying to isolate the year number/the first 4 characters of each line.所以现在我试图隔离年份编号/每行的前 4 个字符。 I'm new to regex, and I know how to get the first 4 characters (I used ^.{4}) but how would I be able to find all EXCEPT for the first 4 characters so that I can replace them with nothing and be left with just the year numbers?我是正则表达式的新手，我知道如何获取前 4 个字符（我使用了 ^.{4}），但是我如何才能找到前 4 个字符除外的所有字符，以便我可以用任何内容替换它们只剩下年份数字？

2 个解决方案

Find: (?<=^\\d{4}).*<\/code> Replace: with nothing查找： (?<=^\\d{4}).*<\/code>替换：无

regex101 Demo<\/a>正则表达式101演示<\/a>

(?<=^\\d{4})<\/code> if a line starts ^<\/code> with 4 digits (?<=^\\d{4})<\/code>如果一行以^<\/code>开头 4 位数字

.*<\/code> match everything else up to line terminators, so the :<\/code> will be included in the match .*<\/code>匹配所有其他内容直到行终止符，因此:<\/code>将包含在匹配中

Since you never matched the 4 digits that you want to keep, you don't have to worry about about any capture groups or replacements.由于您从未匹配要保留的 4 位数字，因此您不必担心任何捕获组或替换。

"

You can你可以

Find : ^(.{4}).+查找： ^(.{4}).+
Replace : $1替换： $1

See the regex demo .请参阅正则表达式演示。 Details :详情：

^ - start of a line (in Visual Studio Code, ^ matches any line start) ^ - 行首（在 Visual Studio Code 中， ^匹配任何行首）
(.{4}) - capturing group #1 that captures any four chars other than line break chars (.{4}) - 捕获组 #1，捕获除换行符以外的任何四个字符
.+ - one or more chars other than line break chars, as many as possible. .+ - 一个或多个除换行符以外的字符，尽可能多。