nchar and substring in R Programming - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of nchar with special characters

What is the output of this R code?

R Programming

text <- "café"
result <- nchar(text)
print(result)

A 4

B 5

C 3

D Error

💡 Hint

Count the number of characters including accented letters.

The nchar function counts characters, including accented ones as single characters. "café" has 4 characters.

❓ Predict Output

intermediate

Substring extraction with start and stop

What does this R code print?

R Programming

text <- "Programming"
result <- substring(text, 4, 7)
print(result)

A "gram"

B "ogra"

C "ming"

D "Prog"

💡 Hint

Remember substring counts characters starting at 1.

substring(text, 4, 7) extracts characters 4 to 7: 'g','r','a','m' forming "gram".

🧠 Conceptual

advanced

Behavior of nchar with different encodings

Which statement about nchar in R is TRUE?

A nchar counts bytes, so accented characters count as more than one.

B nchar always returns the number of bytes, ignoring encoding.

C nchar counts characters, and accented characters count as one character.

D nchar returns the number of words in a string.

💡 Hint

Think about how nchar treats accented letters.

nchar counts characters, not bytes, so accented letters count as one character each.

❓ Predict Output

advanced

Substring with start greater than stop

What is the output of this R code?

R Programming

text <- "DataScience"
result <- substring(text, 5, 3)
print(result)

A Error

B "a"

C "ta"

D ""

💡 Hint

Check what happens if start is greater than stop in substring.

If start > stop, substring returns an empty string "".

❓ Predict Output

expert

Combining nchar and substring for dynamic extraction

What does this R code print?

R Programming

text <- "HelloWorld"
len <- nchar(text)
result <- substring(text, len - 4 + 1, len)
print(result)

A "Hello"

B "World"

C "oWorld"

D "orld"

💡 Hint

Calculate length and extract last 5 characters.

nchar(text) is 10. substring(text, 6, 10) extracts characters 6 to 10: "World".