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x <- seq(0.1,10,0.1) y <- if (x < 5) 1 else 2 I would want the if to operate on every single case instead of operating on the whole vector. What do I have to change?
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R ifelse() Function In R, the ifelse() function is a shorthand vectorized alternative to the standard if...else statement. Most of the functions in R take a vector as input and return a vectorized output.
Multiple Conditions To join two or more conditions into a single if statement, use logical operators viz. && (and), || (or) and ! (not). && (and) expression is True, if all the conditions are true.
%in% operator can be used in R Programming Language, to check for the presence of an element inside a vector. It returns a boolean output, evaluating to TRUE if the element is present, else returns false.
The ifelse function is used to assign one object or another depending on whether the first argument, test, is TRUE or FALSE. It even works as one would hope when test is a vector. test – A logical expression, which may be a vector.
x <- seq(0.1,10,0.1) > x [1] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 [16] 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 [31] 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 [46] 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6.0 [61] 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 [76] 7.6 7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 9.0 [91] 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 10.0 > ifelse(x < 5, 1, 2) [1] 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 [38] 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 [75] 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 y <- if (x < 5) 1 else 2 does not operate on the whole vector (the warning you receive tells you only the first element of the condition will be used). You want ifelse:
y <- ifelse(x < 5, 1, 2) ifelse operates on the whole logical vector, element-by-element. if only accepts one logical value. See ?"if" and ?ifelse
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