Indexing in Vectors
Great! Now you understand how to create a vector and assign names to its values.
To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.
Now, let’s revisit the grades example:
We'll extract the grade for Math and the grade for Literature.
1234567grades <- c(80, 75, 95, 100) # Vector of grades # Assign names to values of grades names(grades) <- c('Math', 'Physics', 'English', 'Literature') # Output the first grade grades[1] # Output Literature grade grades['Literature']
It's also possible to access multiple elements simultaneously:
1234567grades <- c(80, 75, 95, 100) # Vector of grades # Assign names to values of grades names(grades) <- c('Math', 'Physics', 'English', 'Literature') # Output the second and the third grades grades[c(2,3)] # Output Math and Physics grades grades[c('Math','Physics')]
Swipe to start coding
Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.
- Retrieve the price of
'Armchair'using its name rather than its index. - Retrieve the prices for both the
'Dining table'and'Dining chair'using their indices.
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Completion rate improved to 3.85Indexing in Vectors
Sveip for å vise menyen
Great! Now you understand how to create a vector and assign names to its values.
To access specific elements within a vector, you can use indices. The index of the first element is 1, the second element is 2, and so on. To retrieve the n-th element from a vector vec, use the syntax vec[n]. Additionally, if the vector elements have assigned names, you can extract the values by their names by enclosing the name in quotes and square brackets.
Now, let’s revisit the grades example:
We'll extract the grade for Math and the grade for Literature.
1234567grades <- c(80, 75, 95, 100) # Vector of grades # Assign names to values of grades names(grades) <- c('Math', 'Physics', 'English', 'Literature') # Output the first grade grades[1] # Output Literature grade grades['Literature']
It's also possible to access multiple elements simultaneously:
1234567grades <- c(80, 75, 95, 100) # Vector of grades # Assign names to values of grades names(grades) <- c('Math', 'Physics', 'English', 'Literature') # Output the second and the third grades grades[c(2,3)] # Output Math and Physics grades grades[c('Math','Physics')]
Swipe to start coding
Continuing from the previous exercise, you have a vector named prices with each price assigned to a corresponding item name.
- Retrieve the price of
'Armchair'using its name rather than its index. - Retrieve the prices for both the
'Dining table'and'Dining chair'using their indices.
Løsning
Bytt til skrivebordet for virkelighetspraksisFortsett der du er med et av alternativene nedenforTakk for tilbakemeldingene dine!
Awesome!
Completion rate improved to 3.85single
