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Bookmark or Share- r - Why use as.factor() instead of just factor() - Stack OverflowWe can at least learn two performance-related issues from above: For a data frame DF, lapply(DF, as.factor) is much faster than lapply(DF, factor) for type conversion, if many columns are readily factors. That function factor is slow can explain why some important R functions are slow, say table: R: table function suprisingly slow.
- polynomials - Factorise $x^n + 1$ - Mathematics Stack Exchange3. Factorization amounts to root finding. xn = −1 x =ei(2k+1)π/n x n = − 1 x = e i (2 k + 1) π / n. and the factors are. x −ei(2k+1)π/n x − e i (2 k + 1) π / n. for k = 0, ⋯ n − 1 k = 0, ⋯ n − 1 (modulo n n). If you want a factorization with real coefficients only, then consider the roots in conjugate pairs.
- ggplot2: change order of display of a factor variable on an axisThe important point here is the order of the factor levels. The order in the levels is also the order in the plot. You can use rev to reverse the order of the levels like this (note that I just reorder one column in a data.frame):
- polynomials - General factorization of $x^n-y^n$ (n is real ...Yes, it works for n
- r - Changing factor levels with dplyr mutate - Stack OverflowFrom my understanding, the currently accepted answer only changes the order of the factor levels, not the actual labels (i.e., how the levels of the factor are called). To illustrate the difference between levels and labels , consider the following example:
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