Merge pull request #241 from tarunkumark/master

added python dictionary comprehension blog

python/038-dictionary-comprehension.md

@@ -0,0 +1,63 @@
+---
+id: 038-dictionary-comprehension.md
+title: Dictionary Comprehension in Python
+tags:
+  - python
+  - random
+author: Tarun K Kumar
+meta-description: dictionary comprehension in python
+date: 2022-10-24 21:53:39 +0530 
+keywords: python
+categories:
+  - python
+image: assets/images/python/python3.svg
+---
+# Dictionary Comprehension in Python
+
+Dictionary comprehension is a simple method of creating a dictionary without using the dict() method and is similar to the list comprehension concept. Suppose we have a list of keys and list of corresponding values and we want to turn those into a dictionary, then we would usually write something like:  
+
+```python
+keys = ['animal','plant','insect']
+values = ["dog","lemongrass","Weevil"]
+
+dict = {}
+
+for i in range(len(keys)):
+    dict[keys[i]] = values[i]
+
+print(dict)
+```
+which would print:
+```python
+{'animal': 'dog', 'plant': 'lemongrass', 'insect': 'Weevil'}
+```
+Well, we have our end result but the same can be achieved with less code. This is where dictionary comprehension comes in.
+
+The refactored code:
+```python
+keys = ['animal','plant','insect']
+values = ["dog","lemongrass","Weevil"]
+
+print({keys[i]:values[i] for i in range(len(keys))})
+```
+So, lets breakdown that line:
+
+To use dictionary comprehension, a dictionary must be created using `{}` and the following syntax must be followed:
+```python
+dictionary = {key: value for vars in iterable}
+```
+- The `key` and `values` are our lists containing our key:value pairs where we use `i` as indices to populate our dictionary
+
+You can also use conditionals in dictionary comprehension as well:
+```python
+keys = ['animal','plant','insect']
+values = [-1,2,3]
+
+print({keys[i]:values[i] for i in range(len(keys)) if values[i]>0})
+```
+The output:
+```python
+{'plant': 2, 'insect': 3}
+```
+This is a more pythonic and my favourite way of creating dictionaries in python. I hope this article was useful. Thank you for reading.
+