Question

我需要有关正则表达式的帮助才能执行以下操作。我有一个学习科目列表，例如：

subject <- c('x-010', 'x-011', 'x-012', 'x-013', 'x-014', 'x-015', 'x-016', 'x-017', 'x-018', 'x-019', 'x-020', 'x-021', 'x-022', 'x-023', 'x-024', 'x-025', 'x-026', 'x-027', 'x-028', 'x-029', 'x-030')

df <- data.frame(subject)

我想添加一列以按照主题的数量对主题进行分类，例如A组中的1-10，B组中的11-20，C组中的21-30，依此类推。我不知道如何使用正则表达式来做到这一点，只是从以下内容开始：

df <- data.frame(subject) %>% 
mutate(case_when(group = str_detect(subject,

但需要了解如何描述这种模式。

Answer 1

我们可以提取数字部分并使用library(tidyverse) df %>% group_by(grp = paste0("Group ", LETTERS[(as.numeric(str_extract(subject, "[0-9]+"))-1) %/% 10 + 1])) # A tibble: 21 x 2 # Groups: grp [3] # subject grp # <fct> <chr> # 1 x-010 Group A # 2 x-011 Group B # 3 x-012 Group B # 4 x-013 Group B # 5 x-014 Group B # 6 x-015 Group B # 7 x-016 Group B # 8 x-017 Group B # 9 x-018 Group B #10 x-019 Group B # ... with 11 more rows

创建组

import React, { Component } from "react";

const homepg = "Hi! Welcome to my site.";
const aboutpg = "I am a React Web Developer.";
class App extends Component {
  constructor(props) {
    super(props);
    this.state = { PageCon: "" };
    this.homepg = this.homepg.bind(this);
    this.aboutpg = this.aboutpg.bind(this);
  }
  homepg() {
    this.setState({ PageCon: homepg });
  }
  aboutpg() {
    this.setState({ PageCon: aboutpg });
  }
  render() {
    const { PageCon } = this.state;
    return (
      <div className="App">
        <nav>
          <h1 onClick={this.homepg}>Home</h1>
          <h1 onClick={this.aboutpg}>About</h1>
        </nav>
        <p>{PageCon}</p>{" "}
      </div>
    );
  }
}

export default App;

使用正则表达式检测字母数字字符串的范围

1 个答案: