以特定模式开头的字符串 [英] string starting with specific pattern

问题描述

这是一个非常简单的 R 问题，但我找不到答案.

This is very simple R question but I could not find an answer.

我想查找以特定模式开头的字符串.例如如果我有图案"ABC我想在以下向量中提取以 ABC 开头的字符串c("ABCGDFGFD","WWABC","AYBC")

I would like to find strings starting with a specific pattern. e.g. if I have the pattern "ABC and I would like extract strings starting with ABC in the following vector c("ABCGDFGFD","WWABC","AYBC")

此示例的预期结果:TRUE FALSE FALSE

注意:在这个例子中，模式的长度并不总是 3 个字符.它可以更长或更短.

NB: The length of the pattern is not always 3 characters as in this example. It could be longer or shorter.

提前致谢！

推荐答案

Regex 在这种情况下更简单:

Regex is simpler in this case:

grepl("^ABC", x)
[1]  TRUE FALSE FALSE

插入符号 ^ 特殊字符标识行的开头.无需指定要计数的字符数.

The caret ^ special character identifies the beginning of the line. No need to have to specify the amount of characters to count to.

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