R 尝试预测测试数据多于训练数据的标签时的警告消息

当我运行此代码（或任何类似的代码）时：

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x1如果测试数据中的变量名称与训练数据中的变量名称匹配，则警告消失：

x1 <- c(runif(100, 0.0, 10.0))
y1 <- c(runif(100, 0.0, 10.0))

data <- data.frame(x1, y1)
data$label <- with(data, ifelse((x1-5)^2 + (y1-5)^2 < 9, 1, 0))

lm_fit <- lm(formula = label ~ .,data = data)

x_vals <- seq(0, 10, 0.25)
y_vals <- seq(0, 10, 0.25)

grid <- expand.grid(x_vals, y_vals)

colnames(grid) <- c('x1', 'y1')

predict(lm_fit, grid)

x1
x1 <- c(runif(100, 0.0, 10.0))
y1 <- c(runif(100, 0.0, 10.0))

data <- data.frame(x1, y1)
data$label <- with(data, ifelse((x1-5)^2 + (y1-5)^2 < 9, 1, 0))

lm_fit <- lm(formula = label ~ .,data = data)

x_vals <- seq(0, 10, 0.25)
y_vals <- seq(0, 10, 0.25)

grid <- expand.grid(x_vals, y_vals)

colnames(grid) <- c('x1', 'y1')

predict(lm_fit, grid)