head() and tail() in Data Analysis Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to show the first 3 rows of the DataFrame.

Data Analysis Python

df.[1](3)

Drag options to blanks, or click blank then click option'

Atail

Bhead

Cshow

Dfirst

Attempts:

3 left

💡 Hint

Common Mistakes

Using tail() instead of head() to get the first rows.

Using show() which is not a pandas DataFrame method.

Using first() which is not a pandas DataFrame method.

The head() method shows the first rows of a DataFrame. Here, head(3) shows the first 3 rows.

2fill in blank

medium

Complete the code to display the last 5 rows of the DataFrame.

Data Analysis Python

df.[1](5)

Drag options to blanks, or click blank then click option'

Atail

Bhead

Cend

Dlast

Attempts:

3 left

💡 Hint

Common Mistakes

Using head() instead of tail() to get the last rows.

Using end() or last() which are not pandas DataFrame methods.

The tail() method shows the last rows of a DataFrame. Here, tail(5) shows the last 5 rows.

3fill in blank

hard

Fix the error in the code to correctly show the first 4 rows of the DataFrame.

Data Analysis Python

df.[1](4)

Drag options to blanks, or click blank then click option'

Atail

Bfirst

Chead

Dshow

Attempts:

3 left

💡 Hint

Common Mistakes

Using tail() instead of head() to get the first rows.

Using show() which is not a pandas DataFrame method.

To show the first 4 rows, use head(4). Using tail(4) shows the last 4 rows, which is incorrect here.

4fill in blank

hard

Fill both blanks to create a dictionary of word lengths for words longer than 3 characters.

Data Analysis Python

{word: [1] for word in words if len(word) [2] 3}

Drag options to blanks, or click blank then click option'

Alen(word)

B<=

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself as the value instead of its length.

Using <= instead of > in the condition.

The dictionary comprehension maps each word to its length using len(word). The condition len(word) > 3 filters words longer than 3 characters.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase words as keys, their lengths as values, for words longer than 4 characters.

Data Analysis Python

{ [1]: [2] for word in words if len(word) [3] 4 }

Drag options to blanks, or click blank then click option'

Aword.upper()

Blen(word)

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the original word as key instead of uppercase.

Using <= instead of > in the condition.

Using the word itself as value instead of length.

The dictionary keys are uppercase words using word.upper(). The values are word lengths with len(word). The condition len(word) > 4 filters words longer than 4 characters.

Practice

1. What does the head() function do when used on a DataFrame?

easy

A. Shows the last few rows of the DataFrame

B. Deletes the first few rows of the DataFrame

C. Shows the total number of rows in the DataFrame

D. Shows the first few rows of the DataFrame

Solution

1. Step 1: Understand the purpose of head()

   The head() function is designed to display the first few rows of a DataFrame to give a quick look at the data.

2. Step 2: Compare with other options

   tail() shows the last few rows, counting rows is done by len(), and deleting rows is not the function of head().

3. Final Answer:

   Shows the first few rows of the DataFrame -> Option D

4. Quick Check:

   head() = first rows [OK]

Hint: Remember: head = start, tail = end [OK]

Common Mistakes:

• Confusing head() with tail()
• Thinking head() counts rows
• Assuming head() deletes data

2. Which of the following is the correct syntax to show the last 3 rows of a DataFrame named df?

easy

A. df.tail(3)

B. df.head(3)

C. df.last(3)

D. df.end(3)

Solution

1. Step 1: Identify the function for last rows

   The tail() function returns the last rows of a DataFrame, and it accepts a number to specify how many rows.

2. Step 2: Check syntax correctness

   df.tail(3) is correct; head() shows first rows, and last() or end() are not valid pandas functions.

3. Final Answer:

   df.tail(3) -> Option A

4. Quick Check:

   Last rows = tail() [OK]

Hint: Use tail(n) to get last n rows [OK]

Common Mistakes:

• Using head() instead of tail()
• Using non-existent functions like last()
• Wrong method call syntax

3. Given the DataFrame df below:

import pandas as pd
data = {'Name': ['Anna', 'Bob', 'Cara', 'Dan', 'Eva'], 'Age': [23, 35, 45, 29, 40]}
df = pd.DataFrame(data)

What will df.head(2) return?

medium

A. An error because head() needs no arguments

B. Rows with Name Dan and Eva

C. Rows with Name Anna and Bob

D. Rows with Age 45 and 29

Solution

1. Step 1: Understand what head(2) does

   head(2) returns the first 2 rows of the DataFrame.

2. Step 2: Identify the first 2 rows in the DataFrame

   The first two rows have Names 'Anna' and 'Bob' with Ages 23 and 35 respectively.

3. Final Answer:

   Rows with Name Anna and Bob -> Option C

4. Quick Check:

   head(2) = first 2 rows [OK]

Hint: head(n) shows first n rows [OK]

Common Mistakes:

• Thinking head() shows last rows
• Assuming head() cannot take arguments
• Mixing row order

4. What is wrong with this code snippet?

import pandas as pd
data = {'A': [1, 2, 3, 4, 5]}
df = pd.DataFrame(data)
print(df.tail[3])

medium

A. DataFrame creation is incorrect

B. Using square brackets instead of parentheses with tail

C. tail() cannot be used with numbers

D. Missing import statement

Solution

1. Step 1: Check the method call syntax

   The code uses df.tail[3] which uses square brackets. Methods require parentheses.

2. Step 2: Correct the syntax

   It should be df.tail(3) to call the method with argument 3.

3. Final Answer:

   Using square brackets instead of parentheses with tail -> Option B

4. Quick Check:

   Method calls need parentheses [OK]

Hint: Use parentheses () to call functions [OK]

Common Mistakes:

• Using [] instead of () for method calls
• Assuming tail() can't take arguments
• Ignoring Python syntax errors

5. You have a DataFrame df with 1000 rows. You want to quickly check the first 5 and last 5 rows together. Which code snippet correctly shows this?

hard

A. pd.concat([df.head(), df.tail()])

B. df.head() + df.tail()

C. df.head() & df.tail()

D. df.head().append(df.tail())

Solution

1. Step 1: Understand how to combine DataFrames

   To combine two DataFrames vertically, use pd.concat() or append() method.

2. Step 2: Check each option

   df.head() + df.tail() and df.head() & df.tail() are invalid operations for DataFrames. df.head().append(df.tail()) works but is deprecated in recent pandas versions. pd.concat([df.head(), df.tail()]) is the recommended way.

3. Final Answer:

   pd.concat([df.head(), df.tail()]) -> Option A

4. Quick Check:

   Use pd.concat() to combine DataFrames [OK]

Hint: Use pd.concat() to join DataFrames vertically [OK]

Common Mistakes:

• Using + or & operators on DataFrames
• Using deprecated append() method
• Trying to print head() and tail() separately without combining