From afc0555be1c7fa8a02301cca7a43a767b1b37e45 Mon Sep 17 00:00:00 2001
From: eyrei123 <eyrei@aol.com>
Date: Sat, 21 Jun 2025 10:30:26 +0100
Subject: [PATCH 1/5] Pre-TR-Upload 1

---
 how-to-drop-null-values-in-pandas/README.md   | 16 +++++++++++++
 .../drop_a_subset.py                          | 16 +++++++++++++
 .../drop_null_columns.py                      |  9 ++++++++
 .../drop_null_rows.py                         | 17 ++++++++++++++
 .../exercise solutions.py                     | 23 +++++++++++++++++++
 how-to-drop-null-values-in-pandas/grades.csv  |  8 +++++++
 .../sales_data_with_missing_values.csv        | 12 ++++++++++
 7 files changed, 101 insertions(+)
 create mode 100644 how-to-drop-null-values-in-pandas/README.md
 create mode 100644 how-to-drop-null-values-in-pandas/drop_a_subset.py
 create mode 100644 how-to-drop-null-values-in-pandas/drop_null_columns.py
 create mode 100644 how-to-drop-null-values-in-pandas/drop_null_rows.py
 create mode 100644 how-to-drop-null-values-in-pandas/exercise solutions.py
 create mode 100644 how-to-drop-null-values-in-pandas/grades.csv
 create mode 100644 how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv

diff --git a/how-to-drop-null-values-in-pandas/README.md b/how-to-drop-null-values-in-pandas/README.md
new file mode 100644
index 0000000000..253f1dd88d
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/README.md
@@ -0,0 +1,16 @@
+The materials contained in this download are designed to complement the RealPython tutorial [How to Drop Null Values in pandas](https://realpython.com/how-to-drop-null-values-in-pandas/).
+
+You should create a new folder named pandas_nulls on your computer and place each file inside it. You may also consider creating a [Python virtual environment](https://realpython.com/python-virtual-environments-a-primer/) within this folder.
+
+Your download bundle contains the following four files. The first three files contain the code from different tutorial sections, while the fourth contains the solutions to the exercise.
+
+`drop_null_rows.py`        
+`drop_null_columns.py`   
+`drop_a_subset.py`         
+`exercise_solutions.py` 
+
+There are also two data files containing the data used throughout the tutorial:
+
+`sales_data_with_missing_values.csv`
+`grades.csv`
+
diff --git a/how-to-drop-null-values-in-pandas/drop_a_subset.py b/how-to-drop-null-values-in-pandas/drop_a_subset.py
new file mode 100644
index 0000000000..f6e647e9c5
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/drop_a_subset.py
@@ -0,0 +1,16 @@
+import pandas as pd
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+
+sales_data.dropna(axis=0, subset=(["discount", "sale_price"]))
+
+sales_data.dropna(how="all")
+
+sales_data.dropna(thresh=5)
+
+sales_data.dropna(thresh=5, ignore_index=True)
diff --git a/how-to-drop-null-values-in-pandas/drop_null_columns.py b/how-to-drop-null-values-in-pandas/drop_null_columns.py
new file mode 100644
index 0000000000..5982903b54
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/drop_null_columns.py
@@ -0,0 +1,9 @@
+import pandas as pd
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+sales_data.dropna(axis="columns")
diff --git a/how-to-drop-null-values-in-pandas/drop_null_rows.py b/how-to-drop-null-values-in-pandas/drop_null_rows.py
new file mode 100644
index 0000000000..2c438c7610
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/drop_null_rows.py
@@ -0,0 +1,17 @@
+import pandas as pd
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+sales_data
+
+sales_data.isna().sum()
+
+sales_data.dropna()
+
+clean_sales_data = sales_data.dropna()
+
+clean_sales_data = sales_data.dropna(inplace=True)
diff --git a/how-to-drop-null-values-in-pandas/exercise solutions.py b/how-to-drop-null-values-in-pandas/exercise solutions.py
new file mode 100644
index 0000000000..c6701340d3
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/exercise solutions.py	
@@ -0,0 +1,23 @@
+grades = pd.read_csv(
+    "grades.csv",
+).convert_dtypes(dtype_backend="pyarrow")
+
+# 1. Permanently drop the last row of the dataframe.
+
+grades.dropna(how="all", inplace=True)
+
+# 2. Display the rows for the exams that all students have completed.
+
+grades.dropna()
+
+# 3. Display any columns with no missing data.
+
+grades.dropna(axis=1)
+
+# 4. Display the exams students have sat five or more times.
+
+grades.dropna(axis=0, thresh=6)  # Remember there are seven columns.
+
+# 5. Who else would be in the exam hall when both `S2` and `S4` were there?
+
+grades.dropna(subset=["S2", "S4"]).dropna(axis=1, ignore_index=True)
diff --git a/how-to-drop-null-values-in-pandas/grades.csv b/how-to-drop-null-values-in-pandas/grades.csv
new file mode 100644
index 0000000000..b716989147
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/grades.csv
@@ -0,0 +1,8 @@
+Subject,S1,S2,S3,S4,S5,S6
+math,18,,15,20,17,18
+science,26,35,19,,33,
+art,15,,9,17,18,14
+music,14,20,12,20,13,18
+history,18,19,,17,,18
+sport,20,17,20,17,18
+,,,,,
\ No newline at end of file
diff --git a/how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv b/how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv
new file mode 100644
index 0000000000..04036fafc2
--- /dev/null
+++ b/how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv
@@ -0,0 +1,12 @@
+order_number,order_date,customer_name,product_purchased,discount,sale_price
+,09/02/2025,Skipton Fealty,Chili Extra Virgin Olive Oil,TRUE,135.00
+70041,,Carmine Priestnall,,,150.00
+70042,09/02/2025,,Rosemary Olive Oil Candle,FALSE,78.00
+70043,10/02/2025,Lanni D'Ambrogi,,TRUE,19.50
+70044,10/02/2025,Tann Angear,Vanilla and Olive Oil Candle,,13.98
+70045,10/02/2025,Skipton Fealty,Basil Extra Virgin Olive Oil,TRUE,
+70046,11/02/2025,Far Pow,Chili Extra Virgin Olive Oil,FALSE,150.00
+70047,11/02/2025,Hill Group,Chili Extra Virgin Olive Oil,TRUE,135.00
+70048,11/02/2025,Devlin Nock,Lavender and Olive Oil Lotion,FALSE,39.96
+,,,,,
+70049,12/02/2025,Swift Inc,Garlic Extra Virgin Olive Oil,TRUE,936.00

From 20a4c377f208c024805b1f18892c096516c11c3e Mon Sep 17 00:00:00 2001
From: eyrei123 <eyrei@aol.com>
Date: Sat, 21 Jun 2025 10:33:41 +0100
Subject: [PATCH 2/5] Pre-TR-Upload 2 - missing import

---
 how-to-drop-null-values-in-pandas/exercise solutions.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/how-to-drop-null-values-in-pandas/exercise solutions.py b/how-to-drop-null-values-in-pandas/exercise solutions.py
index c6701340d3..239366d025 100644
--- a/how-to-drop-null-values-in-pandas/exercise solutions.py	
+++ b/how-to-drop-null-values-in-pandas/exercise solutions.py	
@@ -1,3 +1,5 @@
+import pandas as pd
+
 grades = pd.read_csv(
     "grades.csv",
 ).convert_dtypes(dtype_backend="pyarrow")

From 8e3dc01aab7d99128d14848a7183828f79d3540b Mon Sep 17 00:00:00 2001
From: eyrei123 <eyrei@aol.com>
Date: Mon, 7 Jul 2025 20:31:04 +0100
Subject: [PATCH 3/5] post-TR1 Update attempt 1

---
 how-to-drop-null-values-in-pandas/drop_a_subset.py     |  3 +++
 how-to-drop-null-values-in-pandas/drop_null_columns.py |  1 +
 how-to-drop-null-values-in-pandas/drop_null_rows.py    |  2 ++
 .../{exercise solutions.py => exercise_solutions.py}   | 10 ++++------
 4 files changed, 10 insertions(+), 6 deletions(-)
 rename how-to-drop-null-values-in-pandas/{exercise solutions.py => exercise_solutions.py} (54%)

diff --git a/how-to-drop-null-values-in-pandas/drop_a_subset.py b/how-to-drop-null-values-in-pandas/drop_a_subset.py
index f6e647e9c5..a8e79aa0a6 100644
--- a/how-to-drop-null-values-in-pandas/drop_a_subset.py
+++ b/how-to-drop-null-values-in-pandas/drop_a_subset.py
@@ -1,5 +1,8 @@
 import pandas as pd
 
+
+pd.set_option("display.max_columns", None)
+
 sales_data = pd.read_csv(
     "sales_data_with_missing_values.csv",
     parse_dates=["order_date"],
diff --git a/how-to-drop-null-values-in-pandas/drop_null_columns.py b/how-to-drop-null-values-in-pandas/drop_null_columns.py
index 5982903b54..080458132c 100644
--- a/how-to-drop-null-values-in-pandas/drop_null_columns.py
+++ b/how-to-drop-null-values-in-pandas/drop_null_columns.py
@@ -1,5 +1,6 @@
 import pandas as pd
 
+
 sales_data = pd.read_csv(
     "sales_data_with_missing_values.csv",
     parse_dates=["order_date"],
diff --git a/how-to-drop-null-values-in-pandas/drop_null_rows.py b/how-to-drop-null-values-in-pandas/drop_null_rows.py
index 2c438c7610..7f68d3f425 100644
--- a/how-to-drop-null-values-in-pandas/drop_null_rows.py
+++ b/how-to-drop-null-values-in-pandas/drop_null_rows.py
@@ -1,5 +1,7 @@
 import pandas as pd
 
+pd.set_option("display.max_columns", None)
+
 sales_data = pd.read_csv(
     "sales_data_with_missing_values.csv",
     parse_dates=["order_date"],
diff --git a/how-to-drop-null-values-in-pandas/exercise solutions.py b/how-to-drop-null-values-in-pandas/exercise_solutions.py
similarity index 54%
rename from how-to-drop-null-values-in-pandas/exercise solutions.py
rename to how-to-drop-null-values-in-pandas/exercise_solutions.py
index 239366d025..21ecd1c410 100644
--- a/how-to-drop-null-values-in-pandas/exercise solutions.py	
+++ b/how-to-drop-null-values-in-pandas/exercise_solutions.py
@@ -1,10 +1,8 @@
-import pandas as pd
-
 grades = pd.read_csv(
     "grades.csv",
 ).convert_dtypes(dtype_backend="pyarrow")
 
-# 1. Permanently drop the last row of the dataframe.
+# 1. Use `.dropna()` in such a way that it permanently drops the row in the dataframe containing only null values.
 
 grades.dropna(how="all", inplace=True)
 
@@ -16,10 +14,10 @@
 
 grades.dropna(axis=1)
 
-# 4. Display the exams students have sat five or more times.
+# 4. Display the exams sat by at least five students.
 
-grades.dropna(axis=0, thresh=6)  # Remember there are seven columns.
+grades.dropna(axis=0, thresh=6) # Remember there are seven columns.
 
-# 5. Who else would be in the exam hall when both `S2` and `S4` were there?
+# 5. Who else was in in every exam that both S2 and S4 sat?
 
 grades.dropna(subset=["S2", "S4"]).dropna(axis=1, ignore_index=True)

From 914ac7d6a74aa60868e294510e624b6e99019798 Mon Sep 17 00:00:00 2001
From: eyrei123 <eyrei@aol.com>
Date: Mon, 7 Jul 2025 20:35:17 +0100
Subject: [PATCH 4/5] post-TR1 Update attempt 2

---
 how-to-drop-null-values-in-pandas/drop_a_subset.py      | 1 -
 how-to-drop-null-values-in-pandas/drop_null_columns.py  | 1 -
 how-to-drop-null-values-in-pandas/exercise_solutions.py | 2 ++
 3 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/how-to-drop-null-values-in-pandas/drop_a_subset.py b/how-to-drop-null-values-in-pandas/drop_a_subset.py
index a8e79aa0a6..c6d7094877 100644
--- a/how-to-drop-null-values-in-pandas/drop_a_subset.py
+++ b/how-to-drop-null-values-in-pandas/drop_a_subset.py
@@ -1,6 +1,5 @@
 import pandas as pd
 
-
 pd.set_option("display.max_columns", None)
 
 sales_data = pd.read_csv(
diff --git a/how-to-drop-null-values-in-pandas/drop_null_columns.py b/how-to-drop-null-values-in-pandas/drop_null_columns.py
index 080458132c..5982903b54 100644
--- a/how-to-drop-null-values-in-pandas/drop_null_columns.py
+++ b/how-to-drop-null-values-in-pandas/drop_null_columns.py
@@ -1,6 +1,5 @@
 import pandas as pd
 
-
 sales_data = pd.read_csv(
     "sales_data_with_missing_values.csv",
     parse_dates=["order_date"],
diff --git a/how-to-drop-null-values-in-pandas/exercise_solutions.py b/how-to-drop-null-values-in-pandas/exercise_solutions.py
index 21ecd1c410..99fe600208 100644
--- a/how-to-drop-null-values-in-pandas/exercise_solutions.py
+++ b/how-to-drop-null-values-in-pandas/exercise_solutions.py
@@ -1,3 +1,5 @@
+import pandas as pd
+
 grades = pd.read_csv(
     "grades.csv",
 ).convert_dtypes(dtype_backend="pyarrow")

From 43ad39e199b2b9cddc55ba2c27ac1e62062c4d55 Mon Sep 17 00:00:00 2001
From: eyrei123 <eyrei@aol.com>
Date: Mon, 7 Jul 2025 20:39:06 +0100
Subject: [PATCH 5/5] post-TR1 Update attempt 3

---
 how-to-drop-null-values-in-pandas/exercise_solutions.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/how-to-drop-null-values-in-pandas/exercise_solutions.py b/how-to-drop-null-values-in-pandas/exercise_solutions.py
index 99fe600208..a1060cb9cc 100644
--- a/how-to-drop-null-values-in-pandas/exercise_solutions.py
+++ b/how-to-drop-null-values-in-pandas/exercise_solutions.py
@@ -18,7 +18,7 @@
 
 # 4. Display the exams sat by at least five students.
 
-grades.dropna(axis=0, thresh=6) # Remember there are seven columns.
+grades.dropna(axis=0, thresh=6)  # Remember there are seven columns.
 
 # 5. Who else was in in every exam that both S2 and S4 sat?