R plot function

Cited from How to Change Plot Options in R

"bty" is the plot function parameter that specifies the type of b round the plot area, use the option bty (box type):

• "o": The default value draws a complete rectangle around the plot.
• "n": Draws nothing around the plot.

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Cited from 15 Questions All R Users Have About Plots

Setting "xaxt" and "yaxt" parameter values equal to "n" removes the axis values of a plot. Any other character set for these arguments specifies the x-axis or y-axis values to be plotted.

Setting "ann" to "FALSE" removes the plotting of axes titles from plotting.

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Cited from Graphics with R

By default, the specified ranges of "xlim" and "ylim" are enlarged by 6%, so that values are not localised to the edges of a plot. In this case, "xaxs" and "yaxs" are set to the default value of "r" ("regular"). In contrary, setting "xaxs" and "yaxs" arguments to the character of "i" ("internal") specifies the limits at the edges of a plot.