interator / generators exmaples

1 files changed, 26 insertions, 0 deletions

diff --git a/iterator.py b/iterator.py
new file mode 100644
index 0000000..2b1e14e
--- /dev/null
+++ b/iterator.py
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+# this class implements an iterator
+# python needs to be told when to stop iterating, this is done by raising StopIteration exception
+
+class ReverseString():
+    def __init__(self, data):
+        self.data = data
+        self.index = len(data)
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self.index == 0:
+            raise StopIteration
+        self.index -= 1
+        return self.data[self.index]
+
+
+def main():
+    foo = ReverseString('foobar')
+    for c in foo:
+        print(c)
+
+
+if __name__ == "__main__":
+    main()