From 7f00161e60677b5301175be409c6b3ca33946fd5 Mon Sep 17 00:00:00 2001
From: chris13888 <43319231+chris13888@users.noreply.github.com>
Date: Sat, 1 Dec 2018 18:55:20 -0800
Subject: [PATCH] Update index.md (#23905)
---
guide/english/python/comparisons/index.md | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/guide/english/python/comparisons/index.md b/guide/english/python/comparisons/index.md
index 52353298d4a..8f8993003c6 100644
--- a/guide/english/python/comparisons/index.md
+++ b/guide/english/python/comparisons/index.md
@@ -34,7 +34,7 @@ We can also chain `<` and `>` operators together. For instance, `3 < 4 < 5` will
In Python, there are two comparison operators which allow us to check to see if two objects are equal. The `is` operator and the `==` operator. However, there is a key difference between them!
-The key difference between 'is' and '==' can be summed up as:
+The key difference between `is` and `==` can be summed up as:
* `is` is used to compare identity
* `==` is used to compare equality
@@ -51,7 +51,7 @@ Next, create a copy of that list.
myListB = myListA
```
-If we use the '==' operator or the 'is' operator, both will result in a True output.
+If we use the `==` operator or the `is` operator, both will result in a True output.
```python
>>> myListA == myListB # both lists contains similar elements
@@ -84,3 +84,17 @@ False # both lists have different reference
To sum up:
* An `is` expression outputs `True` if both variables are pointing to the same reference
* An `==` expression outputs `True` if both variables contain the same data
+
+However, interestingly, there are a few special cases in Python with `is`.
+```python
+>>> a = 5
+>>> b = 5
+>>> a is b
+True
+>>> a = 1000
+>>> b = 1000
+>>> a is b
+False
+```
+
+This is due to how Python is implemented. In Python, small integers (from -5 up to 256, a fast test shows) are cached. You shouldn't rely on this detail – larger integers do not evaluate to `true` when you use `is`. For more information on this topic, view this StackOverflow thread.