如何将字符串连接到现有文件? [英] How do I concatenate string to an existing file?

问题描述

我有一个文本文件(里面有内容)，我想向它附加文本.这是我的代码:

I've got a text file (it has content in it) and I want to append text to it. This is my code:

File outputFile=new File('hello.out');
      outputFile.createSync();
      List<String> readLines=files[i].readAsLinesSync(Encoding.UTF_8);
      for(int j=0;j<readLines.length;j++)
      {

        outputFile.writeAsStringSync(readLines[j], FileMode.APPEND); }

出于某种原因，Dart 在FileMode.APPEND"下放了一条黄线，表示这是一个额外的参数".但是，此链接 http://api.dartlang.org/docs/releases/latest/dart_io/File.html 声称它是可选的.

For some reason Dart put a yellow line under "FileMode.APPEND" and it says that it's an "extra argument". However, this link http://api.dartlang.org/docs/releases/latest/dart_io/File.html claims that it is optional.

推荐答案

FileMode 是一个可选的命名参数，因此您在调用它时必须指定其名称 ('mode').要解决您的问题，请更改此设置:

The FileMode is an optional, named parameter, so you have to specify its name ('mode') when you call it. To solve your problem, change this:

outputFile.writeAsStringSync(readLines[j], FileMode.append);

为此:

outputFile.writeAsStringSync(readLines[j], mode: FileMode.append);

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