1. The line of the iteration file
Copy Code code as follows:
public static ienumerable<string> 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. Using iterators and predicates to filter the rows in a file
Copy Code code as follows:
public static ienumerable<t> where<t> (ienumerable<t> source, predicate<t> predicate)
{
if (Source = NULL | | predicate = NULL)
{
throw new ArgumentNullException ();
}
Return Whereimplemeter (source, predicate);
}
private static ienumerable<t> whereimplemeter<t> (ienumerable<t> source, predicate<t> predicate)
{
foreach (T item in Source)
{
if (predicate (item))
{
Yield return item;
}
}
}
static void Main ()
{
Ienumerable<string> lines = File.ReadAllLines (@ "Your File name");
predicate<string> predicate = delegate (string line)
{
Return line. StartsWith ("using");
};
foreach (String str in where (lines, predicate))
{
Console.WriteLine (str);
}
}
