R ggplot2显示不在数据中的列

我认为ggplot有问题，非常严格，但不知怎么的，它显示的数据不在那里，我如何才能摆脱它似乎显示x=2和5列的空白空间

Data <- structure(list(DQRNiveau = c(0, 1, 3, 4, 6, 7, 8, 0, 1, 3, 4, 6, 7, 8),
              Group = c("Alpha", "Alpha", "Alpha", "Alpha", "Alpha", "Alpha", "Alpha", "Beta", "Beta", "Beta", "Beta", "Beta", "Beta", "Beta"),
              n_Count = c(2L, 4L, 11L, 77L, 45L, 102L, 13L, 2L, 4L, 16L, 103L, 58L, 109L, 13L)),
              .Names = c("DQRNiveau", "Group", "n_Count"), row.names = c(NA, -14L),
              class = c("tbl_df", "tbl", "data.frame"))


ggplot(data = Data, aes(DQRNiveau, y = n_Count, fill = Group)) +
geom_bar(stat = "identity", position = position_dodge(1))  +
scale_x_continuous(breaks = c(Data$DQRNiveau)) 

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Data因为
DQRNiveau
是数字，所以它会创建空格。如果您将其转换为字符，它应该可以正常工作，因为它将其视为一个分类变量

ggplot(data = Data, aes(as.character(DQRNiveau), y = n_Count, fill = Group)) +
  geom_bar(stat = "identity", position = position_dodge(1)) + 
  xlab('DQRNiveau')

您要求的是连续刻度，但在2和5处不连续