Question

如何在node.js中读取文件，搜索字符串并删除行？我尝试过

var fs = require('fs')
fs.readFile('shuffle.txt', function read(err, data) {
if (err) {
throw err;
}

lastIndex = function(){
for (var i = data_array.length - 1; i > -1; i--)
if (data_array[i].match('user1'))
return i;
}()

delete data_array[lastIndex];

});

Answer 1

假设我们有一个文本文件， shuffle.txt 包含以下内容

john
doe
user1 
some keyword
last word

现在，我们阅读 shuffle.txt 文件，然后搜索“ user1 ”关键字。如果任何行包含“ user1 ”，那么我们将删除该行。

var fs = require('fs')
fs.readFile('shuffle.txt', {encoding: 'utf-8'}, function(err, data) {
    if (err) throw error;

    let dataArray = data.split('\n'); // convert file data in an array
    const searchKeyword = 'user1'; // we are looking for a line, contains, key word 'user1' in the file
    let lastIndex = -1; // let say, we have not found the keyword

    for (let index=0; index<dataArray.length; index++) {
        if (dataArray[index].includes(searchKeyword)) { // check if a line contains the 'user1' keyword
            lastIndex = index; // found a line includes a 'user1' keyword
            break; 
        }
    }

    dataArray.splice(lastIndex, 1); // remove the keyword 'user1' from the data Array

    // UPDATE FILE WITH NEW DATA
    // IN CASE YOU WANT TO UPDATE THE CONTENT IN YOUR FILE
    // THIS WILL REMOVE THE LINE CONTAINS 'user1' IN YOUR shuffle.txt FILE
    const updatedData = dataArray.join('\n');
    fs.writeFile('shuffle.txt', updatedData, (err) => {
        if (err) throw err;
        console.log ('Successfully updated the file data');
    });

});

在这里，如果一行包含“ user1 ”关键字，我们将删除整行。新的 shuffle.txt 文件将不再包含带有“ user1”关键字的行。更新后的 shuffle.txt 文件看起来像

john
doe
some keyword
last word

有关更多信息，请检查doc。

查找字符串并删除行-Node.JS

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