Question

例如：

x1 <- data.frame("ID" = c(1:6), 
                  "Position" = c("Left-Striker", 
                                 "Goalkeeper", 
                                 "Right-Striker",
                                 "Striker",
                                 "Centerback",
                                 "Right-Midfield"))

返回：

      ID       Position
   1  1    Left-Striker
   2  2      Goalkeeper
   3  3   Right-Striker
   4  4         Striker
   5  5      Centerback
   6  6  Right-Midfield

我想将所有带有因子的单词“ Striker”重命名为因子“ Striker”。数据框如下所示：

      ID       Position
   1  1         Striker
   2  2      Goalkeeper
   3  3         Striker
   4  4         Striker
   5  5      Centerback
   6  6  Right-Midfield

Answer 1

这会将变量存储为因数，并删除以R为基础的未使用级别：

x1$Position[grepl("Striker",x1$Position)] <- "Striker"
x1$Position <- droplevels(x1$Position)
x1$Position
# [1] Striker        Goalkeeper     Striker        Striker        Centerback     Right-Midfield
# Levels: Centerback Goalkeeper Right-Midfield Striker

您也可以执行以下操作以获得类似的效果（级别可能会有所不同）：

levels(x1$Position)[grepl("Striker",levels(x1$Position))] <- "Striker"
x1$Position
# [1] Striker        Goalkeeper     Striker        Striker        Centerback     Right-Midfield
# Levels: Centerback Goalkeeper Striker Right-Midfield

Answer 2

我们可以使用gsub删除第一个单词

x1$Position <- gsub('(^\\w+-)(Striker)','\\2',x1$Position)

()用于对表达式进行分组

(^\\w+-)第一组搜索一个或多个单词，后跟-

(Striker)的第二组搜索为文字Striker。

\\2意味着丢弃第一组并返回第二组Striker。

Answer 3

这也可以通过forcats软件包来完成：

forcats::fct_collapse(x1$Position, "Striker" = c("Left-Striker", "Striker", "Right-Striker"))

Answer 4

使用正则表达式

package com.example.android.mynewsx2;


    import android.net.Uri;
    import android.util.Log;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    import java.nio.charset.Charset;
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    import java.util.Locale;

    /**
     * Created by Person on 11/08/2018.
     */

    public class QueryUtils {

        public boolean connTimeout = false;
        static String createStringUrl() {
            Uri.Builder builder = new Uri.Builder();
            builder.scheme("http")
                    .encodedAuthority("content.guardianapis.com")
                    .appendPath("search")
                    .appendQueryParameter("order-by", "newest")
                    .appendQueryParameter("show-references", "author")
                    .appendQueryParameter("show-tags", "contributor")
                    .appendQueryParameter("page-size", "175")
                    .appendQueryParameter("q", "")
                    .appendQueryParameter("api-key", "c15d8295-7691-4172-a257-a7d065668eb4");
            String url = builder.build().toString();
            return url;
        }

        static URL createUrl() {
            String stringUrl = createStringUrl();
            try {
                return new URL(stringUrl);
            } catch (MalformedURLException e) {
                Log.e("Queryutils", "Error creating URL: ", e);
                return null;
            }
        }

        private static String formatDate(String rawDate) {
            String jsonDatePattern = "yyyy-MM-dd'T'HH:mm:ss'Z'";
            SimpleDateFormat jsonFormatter = new SimpleDateFormat(jsonDatePattern, Locale.US);
            try {
                Date parsedJsonDate = jsonFormatter.parse(rawDate);
                String finalDatePattern = "MMM d, yyy";
                SimpleDateFormat finalDateFormatter = new SimpleDateFormat(finalDatePattern, Locale.US);
                return finalDateFormatter.format(parsedJsonDate);
            } catch (ParseException e) {
                Log.e("QueryUtils", "Error parsing JSON date: ", e);
                return "";
            }
        }

        static String makeHttpRequest(URL url) throws IOException {
            String jsonResponse = "";

            if (url == null){
                return jsonResponse;
            }
            HttpURLConnection urlConnection = null;
            InputStream inputStream = null;

            try {
                urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestMethod("GET");
                urlConnection.setReadTimeout(10000 /* milliseconds */);
                urlConnection.setConnectTimeout(15000 /* milliseconds */);
                urlConnection.connect();
                if (urlConnection.getResponseCode() == 200){
                    inputStream = urlConnection.getInputStream();
                    jsonResponse = readFromStream(inputStream);
                } else {
                    Log.e("mainActivity", "Error response code: " + urlConnection.getResponseCode());

                }
            } catch (IOException e) {
                Log.e("Queryutils", "Error making HTTP request: ", e);
            } finally {
                if (urlConnection != null) {
                    urlConnection.disconnect();
                }
                if (inputStream != null) {
                    inputStream.close();
                }
            }
            return jsonResponse;
        }

        private static String readFromStream(InputStream inputStream) throws IOException {
            StringBuilder output = new StringBuilder();
            if (inputStream != null) {
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
                BufferedReader reader = new BufferedReader(inputStreamReader);
                String line = reader.readLine();
                while (line != null) {
                    output.append(line);
                    line = reader.readLine();
                }
            }
            return output.toString();
        }

        static List<News> parseJson(String response) {
            ArrayList<News> listOfNews = new ArrayList<>();
            try {
                JSONObject jsonResponse = new JSONObject(response);
                JSONObject jsonResults = jsonResponse.getJSONObject("response");
                JSONArray resultsArray = jsonResults.getJSONArray("results");

                for (int i = 0; i < resultsArray.length(); i++) {
                    JSONObject oneResult = resultsArray.getJSONObject(i);
                    String webTitle = oneResult.getString("webTitle");
                    String url = oneResult.getString("webUrl");
                    String date = oneResult.getString("webPublicationDate");
                    date = formatDate(date);
                    String section = oneResult.getString("sectionName");
                    JSONArray tagsArray = oneResult.getJSONArray("tags");
                    String author = "";

                    if (tagsArray.length() == 0) {
                        author = null;
                    } else {
                        for (int j = 0; j < tagsArray.length(); j++) {
                            JSONObject firstObject = tagsArray.getJSONObject(j);
                            author += firstObject.getString("webTitle") + ". ";
                        }
                    }
                    listOfNews.add(new News(webTitle, author, url, date, section));
                }
            } catch (JSONException e) {
                Log.e("Queryutils", "Error parsing JSON response", e);
            }
            return listOfNews;
        }
    }

来自stringr

[]中可以使用许多预构建的类：



[：alpha：]：字母。

library(stringr) x1$Position <- str_replace_all(x1$Position, "[:alpha:]+-?Striker", "Striker")表示一个或多个。 +在您的字符串中。

重命名一个因子的多个级别，所有这些因子都包含相同的词

4 个答案: