When you create a series of plots with ggplot2, how can you programmatically add a number in the plot title to show which plot it is in the series? The examples below have Plot 1, Plot 2 and Plot 3 hard coded in the title; how can ggplot put in 1, 2, 3, etc.? The plots will be inserted in a document at different places.,
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Ggplot2和一系列图表标题中的递增数字
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