Avoid ggplot by sorting label x-axis while plotting geom_bar() ggplot code example
Example: ggplot geom_bar x axis labels
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p + scale_x_discrete(limit = c("I1", "SI2", "SI1"),
labels = c("Ione","SItwo","SIone"))
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p + scale_x_discrete(limit = c("I1", "SI2", "SI1"),
labels = c("Ione","SItwo","SIone"))