strings

strings/string_manipulation/solution/strings.py

@@ -15,18 +15,24 @@ class String:
     
     def __add__(self, other: Str) -> 'String':
         return String(self.__s + str(other))
-            
-    def __iadd__(self, other: Str) -> 'String':
-        return self + other
     
+    def __radd__(self, other: Str) -> 'String':
+        return String(str(other) + self.__s)
+            
     def __len__(self) -> int:
         return len(self.__s)
     
     def __eq__(self, other: Str) -> bool:
         return str(self) == str(other)
+    
+    def __iter__(self) -> Iterator[chr]:
+        pass
+        for i in range(0, len(self)):
+            yield chr(self.__s[i])
+        raise StopIteration
             
-    def concat(self, other: Str) -> None:
-        self + other
+    def concat(self, other: Str) -> 'String':
+        return self + other
         
     def contains(self, other: Str) -> bool:
         s = str(other)
@@ -38,9 +44,6 @@ class String:
             else:
                 s = str(other)
         return len(s) == 0
-    
-    def concat(self, other: Str) -> None:
-        self.__s += str(other)
         
     def substring(self, start: int, end: int) -> 'String':
         substr: str = ""
@@ -49,39 +52,41 @@ class String:
                 substr += c
         return substr
     
-    def strip(self, chars: Str = ' ' + '\n' + '\t' + '\r') -> None:
+    def strip(self, chars: Str = ' ' + '\n' + '\t' + '\r') -> 'String':
         i = 0
         while i < len(self) and self.__s[i] in chars:
             i += 1
         j: int = len(self) - 1
         while i <= j and self.__s[j] in chars:
             j -= 1
-        self.__s: str = str(self)[i:j + 1]
+        return String(str(self)[i:j + 1])
         
-    def replace(self, old: Str, new: Str, count = -1) -> None:
+    def replace(self, old: Str, new: Str, count = -1) -> 'String':
         o = str(old)
         n = str(new)
+        new_str = self.__s
         j = 0
-        while count > 0 or (count < 0 and j < len(self)):
+        while count > 0 or (count < 0 and j < len(new_str)):
             i: int = j
-            while len(o) > 0 and j < len(self):
-                if o[0] == self.__s[j]:
+            while len(o) > 0 and j < len(new_str):
+                if o[0] == new_str[j]:
                     o: str = o[1:]
                     j += 1
                 else:
                     j += 1
                     break
             if len(o) <= 0:
-                self.__s = self.__s[:i] + n + self.__s[j:]
+                new_str = new_str[:i] + n + new_str[j:]
                 j += len(new) - len(old)
                 count -= 1
             o = str(old)
+        return new_str
     
-    def add_prefix(self, prefix: Str) -> None:
-        self.__s = str(prefix) + self.__s
+    def add_prefix(self, prefix: Str) -> 'String':
+        return prefix + self
         
-    def add_suffix(self, suffix: Str) -> None:
-        self.__s += str(suffix)
+    def add_suffix(self, suffix: Str) -> 'String':
+        return self + suffix
         
     def join[T](self, xs: Iterator[T]) -> 'String':
         output = String("")