Added str.ljust()

python/common/org/python/types/Str.java

@@ -1,4 +1,5 @@
 package org.python.types;
+import org.Python;
 
 import java.util.ArrayList;
 
@@ -831,10 +832,38 @@ public org.python.Object join(org.python.Object iterable) {
     }
 
     @org.python.Method(
-        __doc__ = ""
-    )
-    public org.python.Object ljust() {
-        throw new org.python.exceptions.NotImplementedError("ljust() has not been implemented.");
+        __doc__ = "S.ljust(width, fillChar=' ') -> str\nReturns the string left justified in a string of length width." + 
+        "\nPadding is done using the specified fillchar (default is a space)." +
+        "\nThe original string is returned if width is less than len(s)",
+        args = {"width"},
+        default_args = {"fillChar"}
+    )
+    public org.python.Object ljust(org.python.Object width, org.python.Object fillChar) {
+        java.lang.String ch = new java.lang.String();
+        if (fillChar instanceof org.python.types.Str) {
+        	if(((org.python.types.Str) fillChar).value.length() != 1) {
+        		throw new org.python.exceptions.TypeError("The fill character must be exactly one character long");
+        	}
+        	ch = ((org.python.types.Str) fillChar).value;
+        } else if (fillChar == null) {
+        	ch = " ";
+        } else {
+        	throw new org.python.exceptions.TypeError("The fill character cannot be converted to Unicode");
+        }
+        if (width instanceof org.python.types.Int) {
+        	int w = (int)((org.python.types.Int) width).value;
+        	if (w < this.value.length()) {
+        		return new org.python.types.Str(this.value);
+        	}
+        	java.lang.StringBuffer str = new java.lang.StringBuffer(w);
+        	str.append(this.value);
+        	int balance = w - this.value.length();
+        	for (int i = 0; i < balance; i++) {
+        		str.append(ch); 
+        	}
+        	return new org.python.types.Str(str.toString());
+        }
+        return new org.python.exceptions.TypeError("integer argument expected, got " + Python.typeName(width.getClass()));
     }
 
     @org.python.Method(

tests/datatypes/test_str.py

@@ -313,6 +313,26 @@ def test_center(self):
             except AttributeError as err:
                 print(err)
             """)
+        def test_ljust(self):
+        self.assertCodeExecution("""
+            s = "abc"
+            print(s.ljust(5, "P"))
+            print(s.ljust(2))
+            print(s.ljust(15, "0"))
+            try:
+                print(s.ljust(16, 5.6))
+            except TypeError as err:
+                print(err)
+            try:
+                print(s.ljust(5.0, "P"))
+            except TypeError as err:
+                print(err)
+            s = 9
+            try:
+                print(s.ljust(8))
+            except AttributeError as err:
+                print(err)
+            """)
 
 
 class UnaryStrOperationTests(UnaryOperationTestCase, TranspileTestCase):