R Programming: Change the first Level of a Factor

R Programming: Factors Exercise-2 with Solution

Write a R program to change the first level of a factor with another level of a given factor.

Sample Solution :

R Programming Code :

# Create a character vector with elements "a", "b", "a", "c", "b"
v = c("a", "b", "a", "c", "b")

# Print the original vector
print("Original vector:")
print(v)

# Convert the vector to a factor
f = factor(v)

# Print the factor of the vector
print("Factor of the said vector:")
print(f)

# Change the first level of the factor to "e"
levels(f)[1] = "e"

# Print the updated factor with the new level
print(f)

Output:

[1] "Original vector:"
[1] "a" "b" "a" "c" "b"
[1] "Factor of the said vector:"
[1] a b a c b
Levels: a b c
[1] e b e c b
Levels: e b c                         

Explanation:

• v = c("a", "b", "a", "c", "b"): A character vector v is created with elements "a", "b", "a", "c", and "b".
• print("Original vector:"): The message "Original vector:" is printed to the console.
• print(v): The original vector v is printed, displaying its elements.
• f = factor(v): The vector v is converted into a factor object f. Factors represent categorical data in R.
• print("Factor of the said vector:"): The message "Factor of the said vector:" is printed to the console.
• print(f): The factor f is printed, showing its levels and the values associated with each level.
• levels(f)[1] = "e": The first level of the factor f (which is "a") is renamed to "e".
• print(f): The updated factor f is printed, now showing the first level as "e" instead of "a".

R Programming Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a R program to find the levels of factor of a given vector.
Next: Write a R program to create an ordered factor from data consisting of the names of months.