New generators-iterators tag

bot/resources/tags/generators-iterators.md

@@ -0,0 +1,43 @@
+---
+aliases: ["generators", "iterators", "yield"]
+embed:
+    title: "Generators and Iterators"
+---
+
+[Iterators](https://docs.python.org/3/glossary.html#term-iterator) are objects that support iteration.
+
+[Generators](https://docs.python.org/3/glossary.html#term-generator) are extended Iterators, which provide a simple way to create Iterators using yield functions or expressions.
+
+**Generator Functions**
+
+A generator function can be created by using one or more `yield` statements. Here is an example of how a `read_lines` function returning a `list` can instead use `yield` to return `Generator`
+```py
+def read_lines(file_name):
+    lines = []
+    with open(file_name, "r") as f:
+        for line in f:
+            lines.append(line.strip())
+    return lines
+
+def read_lines(file_name):
+    with open(file_name, "r") as f:
+        for line in f:
+            yield line.strip()
+```
+Generators can be a memory-efficient alternative to lists in many situations.
+**Generator Expressions**
+
+Generators can also be created by `for` clauses inside [expressions](https://docs.python.org/3/glossary.html#term-generator-expression), similar to creating a list comprehension.
+
+```py
+foo = (x * 2 for x in range(5))
+
+for num in foo:
+    print(num)
+```
+
+**More Information**
+
+• Generators and Iterators can also be created as custom classes by implementing their required [abstract methods](https://docs.python.org/3/library/collections.abc.html#collections-abstract-base-classes-1).
+
+• Check out the [Real python article](https://realpython.com/introduction-to-python-generators/) for a more in-depth view of Generators and their use-cases!