Using R as a Calculator
All complex analyses comprise sequences of multiple simple operations. To get acquainted with R and "build trust," please read about these operations you can implement in the R (RStudio) console and immediately see the results. Run the codes on your computer. Do you get the same outputs? Try changing some of the code to see how the outputs will change. You should be able to guess what kind of output you can get from any of these simple operations.
Order of Operations
When using R as a calculator, the order of operations is the same as you would have learned back in school.
From highest to lowest precedence:
- Parentheses:
(,) - Exponents:
^or** - Multiply:
* - Divide:
/ - Add:
+ - Subtract:
-
3 + 5 * 2| Output |
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Use parentheses to group operations to force the order of evaluation if it differs from the default or to clarify what you intend.
(3 + 5) * 2| Output |
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This can get unwieldy when not needed but clarifies your intentions. Remember that others may later read your code.
(3 + (5 * (2 ^ 2))) # hard to read
3 + 5 * 2 ^ 2 # clear, if you remember the rules
3 + 5 * (2 ^ 2) # if you forget some rules, this might helpThe text after each line of code is called a
"comment." Anything that follows after the hash (or octothorpe) symbol
# is ignored by R when it executes code.
Really small or large numbers get a scientific notation:
2/10000| Output |
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Which is shorthand for "multiplied by 10^XX". So 2e-4
is shorthand for 2 * 10^(-4).
You can write numbers in scientific notation too:
5e3 # Note the lack of minus here| Output |
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