Comparing Things
We can also do comparisons in R:
1 == 1 # equality (note two equals signs, read as "is equal to")
1 != 2 # inequality (read as "is not equal to")
1 < 2 # less than
1 <= 1 # less than or equal to
1 > 0 # greater than
1 >= -9 # greater than or equal to
Tip: Comparing Numbers
A word of warning about comparing numbers: you should
never use ==
to compare two numbers unless they are
integers (a data type which can specifically represent
only whole numbers).
Computers may only represent decimal numbers with a
certain degree of precision, so two numbers which look
the same when printed out by R, may actually have
different underlying representations and therefore be
different by a small margin of error (called Machine
numeric tolerance).
Instead you should use the all.equal
function.