KentarouKanno/File Operation.md

## File Operation.md

      
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              File Operation.md
            
          
    File Operation

★ ファイルへの書き込み
let fileName = "data.txt"
let text = "abcde"

if let dir: NSString = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first {
    
    let filePath = dir.stringByAppendingPathComponent(fileName)
    
    do {
        
        try text.writeToFile(filePath, atomically: false, encoding: NSUTF8StringEncoding)
    } catch {
        //エラー処理
    }
}
★ ファイルの読み込み
let fileName = "data.txt"

if let dir: NSString = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first {
    
    let filePath = dir.stringByAppendingPathComponent(fileName)
    
    do {
        
        let text = try NSString(contentsOfFile: filePath, encoding: NSUTF8StringEncoding)
        print(text)
        
    } catch {
        //エラー処理
    }
}
★ ファイルに対して文字列を追加する(.txtの場合)
if let dir: NSString = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true).first {
    
    let filePath = dir.stringByAppendingPathComponent(fileName)
    
    let output = NSOutputStream(toFileAtPath: filePath, append: true)
    output?.open()
    let text = "test" // 末尾に追加する文字列
    let cstring = text.cStringUsingEncoding(NSUTF8StringEncoding)
    let bytes = UnsafePointer<UInt8>(cstring!)
    let size = text.lengthOfBytesUsingEncoding(NSUTF8StringEncoding)
    output?.write(bytes, maxLength: size)
    output?.close()
}