每次运行程序时，我都会使用以下代码将一些日志写入新文件。但似乎os.path.exists（）每次运行时都会创建所有文件。我在OS X 10.10.3上使用mac。
.exists()如果我在终端中运行python脚本，即＆＃34; python ./that_code.py"或者在IDE中，.exists()将创建文件。但是只需在IPython中运行MediaPlayer soundofletter;
int indeks=0;
String[] letter = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
int [] sound = {R.raw.a , R.raw.b , R.raw.c , R.raw.d , R.raw.e , R.raw.f ,
R.raw.g , R.raw.h , R.raw.i , R.raw.j , R.raw.k , R.raw.l ,
R.raw.m , R.raw.n , R.raw.o , R.raw.p , R.raw.q , R.raw.r ,
R.raw.s , R.raw.t , R.raw.u , R.raw.v , R.raw.w , R.raw.x , R.raw.y , R.raw.z};
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.lihathuruf);
Gallery g = (Gallery) findViewById(R.id.gallery1);
g.setAdapter(new ImageAdapter(this));
g.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(@SuppressWarnings("rawtypes") AdapterView parent, View v, int position, long id) {
Toast.makeText(LihatHuruf.this, "" + letter[position], Toast.LENGTH_SHORT).show();
}
});
}
public ImageAdapter(Context c) {
mContext = c;
TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);
mGalleryItemBackground = a.getResourceId(
R.styleable.Gallery1_android_galleryItemBackground, 0);
a.recycle();
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mImageIds[position]);
i.setLayoutParams(new Gallery.LayoutParams(250, 300));
i.setScaleType(ImageView.ScaleType.FIT_XY);
i.setBackgroundResource(mGalleryItemBackground);
return i;
}
就不会创建文件。
答案 0 :(得分：2)
你完全正确
for idx in range(0, 100):
if os.path.exists(str(idx) + ".out.txt"):
continue
else:
output_file = open(str(idx) + ".out.txt", "w")
...创建所有相关文件。您完全错误它是os.path.exists()行。
output_file = open(str(idx) + ".out.txt", "w")
...创建为打开而打开的文件。将该行替换为pass，或者只是完全删除else子句，您将看到不再创建该项。
顺便说一下 - 在Go中，这种模式被认为是不好的做法，并且有人想要确保存在这些数百个文件，建议无条件地打开它们进行写入，而不检查它们是否先前存在过。这种方法避免了竞争条件 - 如果文件的存在在os.path.exists()电话和open()之间发生变化，会发生什么情况，并且还会减少stat()次来电。