nchar and substring in R Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the number of characters in the string.

R Programming

length <- [1]("Hello World")

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

Asubstring

Bnchar

Clength

Dstr_length

Attempts:

3 left

💡 Hint

Common Mistakes

Using substring instead of nchar.

Using length which counts elements in a vector, not characters.

The nchar() function returns the number of characters in a string in R.

2fill in blank

medium

Complete the code to extract the first 5 characters from the string.

R Programming

part <- [1]("Programming", 1, 5)

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Asubstring

Bstr_sub

Csubstr

Dnchar

Attempts:

3 left

💡 Hint

Common Mistakes

Using nchar which counts characters, not extracts.

Using str_sub which is from a different package.

The substring() function extracts a substring from a string given start and end positions.

3fill in blank

hard

Fix the error in the code to correctly extract characters 3 to 7 from the string.

R Programming

result <- substring("DataScience", [1], 7)

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A1

B7

C0

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 7 as start position which extracts only one character.

Using 0 which is invalid in R string indexing.

The start position should be 3 to extract characters from position 3 to 7.

4fill in blank

hard

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

R Programming

lengths <- list([1] = nchar(word) for word in words if nchar(word) [2] 3)

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Aword

B>

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using == which selects words exactly 3 characters long.

Using < which selects shorter words.

We use word as the key and check if word length is greater than 3 with >.

5fill in blank

hard

Fill all three blanks to create a named vector of substring results for words longer than 4 characters.

R Programming

result <- c([1] = substring(word, 1, 3) for word in words if nchar(word) [2] 4 and word [3] "Data")

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

Aword

B>

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of != which would include only "Data".

Using < instead of > which selects shorter words.

We use word as the name, select words with length greater than 4, and exclude the word "Data" using !=.