adding 2nd exercise my solution

Author: RohanSaxena2020

2.py

@@ -0,0 +1,84 @@
+# ### Bubble Sort Exercise
+
+# Modify [bubble_sort function](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/2_BubbleSort/bubble_sort.py) such that it can sort following list of transactions happening in an electronic store,
+# ```
+# elements = [
+#         { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
+#         { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
+#         { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
+#         { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
+#     ]
+# ``` 
+# bubble_sort function should take key from a transaction record and sort the list as per that key. For example,
+# ```
+# bubble_sort(elements, key='transaction_amount')
+# ```
+# This will sort elements by transaction_amount and your sorted list will look like,
+# ```
+# elements = [
+#         { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
+#         { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
+#         { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
+#         { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
+#     ]
+# ``` 
+# But if you call it like this,
+# ```
+# bubble_sort(elements, key='name')
+# ```
+# output will be,
+# ```
+# elements = [
+#         { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
+#         { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
+#         { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
+#         { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
+#     ]
+# ``` 
+
+# base bubble_sort. you can use this to sort strings too
+def bubble_sort(elements):
+    size = len(elements)
+
+    for i in range(size-1):
+        swapped = False
+        for j in range(size-1-i):
+            if elements[j] > elements[j+1]:
+                tmp = elements[j]
+                elements[j] = elements[j+1]
+                elements[j+1] = tmp
+                swapped = True
+
+        if not swapped:
+            break
+
+def bubble_sort_by_key(elements, key):
+    size = len(elements)
+
+    for i in range(size-1):
+        swapped = False
+        for j in range(size-1-i):
+            if elements[j][key] > elements[j+1][key]:
+                tmp = elements[j]
+                elements[j] = elements[j+1]
+                elements[j+1] = tmp
+                swapped = True
+
+        if not swapped:
+            break
+
+
+elements = [5,9,2,1,67,34,88,34]
+elements = [1,2,3,4,2]
+elements = ["mona", "dhaval", "aamir", "tina", "chang"]
+
+bubble_sort(elements)
+print(elements)
+
+elements2 = [ { 'name': 'kathy',  'transaction_amount': 200,  'device': 'vivo'},
+        { 'name': 'dhaval', 'transaction_amount': 400,  'device': 'google pixel'},
+        { 'name': 'aamir',  'transaction_amount': 800,  'device': 'iphone-8'},
+        { 'name': 'mona',   'transaction_amount': 1000, 'device': 'iphone-10'},
+    ]
+bubble_sort_by_key(elements2,key='transaction_amount')
+print(elements2)