Named vectors in R Programming - Step-by-Step Execution

Concept Flow - Named vectors

Create vector values

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Assign names to each element

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Access elements by name or position

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Use named vector in calculations or display

Create a vector, assign names to each element, then access or use elements by their names or positions.

Execution Sample

R Programming

scores <- c(90, 85, 78)
names(scores) <- c("Math", "Science", "English")
scores["Science"]

Create a numeric vector with scores, name each score by subject, then access the Science score by its name.

Execution Table

Step	Action	Vector Content	Names	Access/Output
1	Create vector with values 90, 85, 78	[90, 85, 78]	NULL	Vector created without names
2	Assign names Math, Science, English	[90, 85, 78]	[Math, Science, English]	Names assigned to each element
3	Access element by name 'Science'	[90, 85, 78]	[Math, Science, English]	85
4	Access element by position 1	[90, 85, 78]	[Math, Science, English]	90
5	Print entire named vector	[90, 85, 78]	[Math, Science, English]	Math=90, Science=85, English=78

💡 All steps complete, vector created, named, and accessed successfully

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
scores	NULL	[90, 85, 78]	[90, 85, 78]	[90, 85, 78]	[90, 85, 78] with names Math, Science, English

Key Moments - 3 Insights

Why does the vector have NULL names at first?

At Step 1 in the execution_table, the vector is created without names, so names are NULL until assigned in Step 2.

How can we access elements by name instead of position?

As shown in Step 3, after assigning names, we can use scores["Science"] to get the value 85 by name.

What happens if we try to access a name that does not exist?

Accessing a non-existent name returns NA or an error; this is not shown here but is important to remember.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of scores after Step 2?

A [85, 78, 90] with names Math, Science, English

B [90, 85, 78] with NULL names

C [90, 85, 78] with names Math, Science, English

D NULL

💡 Hint

Check the Vector Content and Names columns at Step 2 in the execution_table

At which step do we access the element by its name?

A Step 2

B Step 3

C Step 1

D Step 4

💡 Hint

Look for the Access/Output column showing access by name in the execution_table

If we change the name 'Science' to 'Physics', which step's output changes?

A Step 2

B Step 1

C Step 3

D Step 5

💡 Hint

Names are assigned in Step 2, so changing a name affects that step's Names column

Concept Snapshot

Named vectors in R:
- Create vector: c(1,2,3)
- Assign names: names(vec) <- c("a","b","c")
- Access by name: vec["b"]
- Names help identify elements clearly
- Useful for readable code and data

Full Transcript

This visual trace shows how to create a named vector in R. First, a numeric vector is created with values 90, 85, and 78. Initially, the vector has no names. Then, names are assigned to each element: Math, Science, and English. After naming, elements can be accessed by their names, for example, scores["Science"] returns 85. The variable tracker shows the vector's state changes, especially the addition of names. Key moments clarify why names start as NULL and how to access elements by name. The quiz tests understanding of vector content and name assignment steps.