問題描述
逐行讀取文件並基於它將換行符寫入同一文件 ‑ nodejs (Reading a file line by line and based on it write newlines to same file ‑ nodejs)
如果每一行都滿足某些條件，我需要逐行讀取文件並在讀取時將換行符寫入同一個文件。最好的方法是什麼。
參考解法
方法 1:
function (file, callback) {
fs.readFile(file, (err, 'utf8', data) => {
if (err) return callback(err);
var lines = data.split('\n');
fs.open(file, 'w', (err, fd) => {
if (err) return callback(err)
lines.forEach(line => {
if (line === 'meet your condition') {
// do your write using fs.write(fd, )
}
})
callback();
})
})
}
</code></pre>
方法 2:
use node fs module with the help of fs you can perform operation asynchronously as well as synchronously. below is as an example of asynchronously
function readWriteData(savPath, srcPath) {
fs.readFile(srcPath, 'utf8', function (err, data) {
if (err) throw err;
//Do your processing, MD5, send a satellite to the moon or can add conditions , etc.
fs.writeFile (savPath, data, function(err) {
if (err) throw err;
console.log('complete');
});
});
}
Synchronously example
function readFileContent(srcPath, callback) {
fs.readFile(srcPath, 'utf8', function (err, data) {
if (err) throw err;
callback(data);
}
);
}
function writeFileContent(savPath, srcPath) {
readFileContent(srcPath, function(data) {
fs.writeFile (savPath, data, function(err) {
if (err) throw err;
console.log('complete');
});
});
}
(by ShyamSundar R、Simon、mohan rathour)
參考文件