如何在swift中将快速更新字符串附加到文件中 [英] How to append fast updating strings to file in swift
本文介绍了如何在swift中将快速更新字符串附加到文件中的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
当传感器在方法中更新时,我想将传感器数据写入文件。我需要在更新时附加数据,但是当我尝试时,我的文件会覆盖最后一个传感器输出。
I want to write sensor data to a file as the sensor updates within the method. I need to append the data as it updates, but my file overwrites with the last sensor output when I try to.
func startAccel(fileName: String, fileURL: URL) ->Void{ //Starting accelerometer
motionManager.accelerometerUpdateInterval = 1.0 / Double(hz) //determines refresh speed
motionManager.startAccelerometerUpdates(to: OperationQueue.current!){ (data, error) in
if let myData = data{
do{
let newLine = "Accelerometer, \(myData.acceleration.x), \(myData.acceleration.y),\(myData.acceleration.z)\n"
try newLine.write(to: fileURL, atomically: false, encoding: .utf8)
try print(String(contentsOf: fileURL, encoding:.utf8))
}catch{
print("yeah that didn't work sorry bub")
}
}
}
}
此代码每隔ti覆盖一次文件我调用了newLine.write(),该函数没有附加选项。如何在收集文件时将传感器输出附加到文件中?
This code overwrites the file every time newLine.write() is called, and there is no append option for that function. How can I append the sensor output to the file as it collects it?
推荐答案
只需尝试使用此
//MARK:- Extension for String
extension String
{
func appendLineToURL(fileURL: URL) throws
{
try (self + "\n").appendToURL(fileURL: fileURL)
}
func appendToURL(fileURL: URL) throws
{
let data = self.data(using: String.Encoding.utf8)!
try data.append(fileURL: fileURL)
}
}
//MARK:- Extension for File data
extension Data
{
func append(fileURL: URL) throws {
if let fileHandle = FileHandle(forWritingAtPath: fileURL.path)
{
defer
{
fileHandle.closeFile()
}
fileHandle.seekToEndOfFile()
fileHandle.write(self)
}
else
{
try write(to: fileURL, options: .atomic)
}
}
}
用法:
try newLine.appendToURL(fileURL: path!)
这些扩展将附加您正好想要的NewLine,
These Extension will Append Your NewLine Which you exactly looking for to Do,
这只会替换路径上的Line
try newLine.write(to: fileURL, atomically: false, encoding: .utf8)
这将使用现有数据作为新行附加数据
try newLine.appendToURL(fileURL: path!)
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