How to Use iterator to traverse File Information

This article provides a detailed analysis of file traversal information using the iterator. For more information, see

This article provides a detailed analysis of file traversal information using the iterator. For more information, see

1. iterate the row of the file

The Code is as follows:

Public static IEnumerable ReadLines (string fileName)
{
Using (TextReader reader = File. OpenText (fileName ))
{
String line;
If (line = reader. ReadLine ())! = Null)
{
Yield return line;
}
}
}
Static void Main ()
{
Foreach (string line in Iterator. ReadLines (""))
{
Console. WriteLine (line );
}
}

2. Use the iterator and predicate to filter rows in the file.

The Code is as follows:

Public static IEnumerable Where (IEnumerable Source, Predicate Predicate)
{
If (source = null | predicate = null)
{
Throw new ArgumentNullException ();
}
Return WhereImplemeter (source, predicate );
}
Private static IEnumerable WhereImplemeter (IEnumerable Source, Predicate Predicate)
{
Foreach (T item in source)
{
If (predicate (item ))
{
Yield return item;
}
}
}
Static void Main ()
{
IEnumerable Lines = File. ReadAllLines (@ "your file name ");
Predicate Predicate = delegate (string line)
{
Return line. StartsWith ("using ");
};
Foreach (string str in where (lines, predicate ))
{
Console. WriteLine (str );
}

}

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