数字变量的比较

Question

我需要将table的联接结果留给生成的序列。因为它没有按预期工作（某些行丢失），我试图比较两个变量中的值。为什么df$c的某些值不等于使用seq()生成的值？

# Sample data
a <- runif(100)
b <- runif(100) > .5
step <- .1

# This is what I do in my real task
df <- as.data.frame.matrix(table(trunc(a / step) * step, b))
df$c <- as.numeric(rownames(df))

# Would like to join, but comparsion of df$c and generated sequence
# return FALSE for some elements.
df$c == seq(0, 0.9, step)

# Returns>  [1]  TRUE  TRUE  TRUE FALSE  TRUE  TRUE FALSE FALSE  TRUE  TRUE