我正在尝试在包含数据框名称的多个数据框架中创建一个列。当他们被附加时就是这样，我知道他们来自哪里。对于每个数据帧，这很容易手动完成：
# create some example data that need joining
Pb = c(5, 6, 4, 5, 7)
depth = c(1, 2, 3, 4, 5)
df1 <- data.frame(Pb, depth)
df2 <- df1 - 0.5
# add a column to each with the name of the original dataframe
df1$label <- deparse( substitute(df1) )
df2$label <- deparse( substitute(df2) )
产生所需的输出：
> df1
Pb depth label
1 5 1 df1
2 6 2 df1
3 4 3 df1
4 5 4 df1
5 7 5 df1
> df2
Pb depth label
1 4.5 0.5 df2
2 5.5 1.5 df2
3 3.5 2.5 df2
4 4.5 3.5 df2
5 6.5 4.5 df2
我正在尝试创建一个接受数据帧列表并执行相同操作的函数，但我在deparse(substitute(x))中使用lapply时遇到了困难。我的（不工作）代码如下：
label_tool = function(list) {
addlabels = function(x){ x$labels<-deparse(substitute(x)) }
list <- lapply( list, addlabels )
return(df)
}
# example usage (see above)
list <- list( df1, df2 )
list <- label_tool(list)
我看到others已设法在deparse(substitute(x))中使用lapply，但坦率地说，我不知道如何使用<?php
header('Content-Type: application/json');
$con3 = mysqli_connect("p:localhost", "root", "", "");
if (mysqli_connect_errno($con)) {
echo "Failed to connect to DataBase: " . mysqli_connect_error();
} else {
$data_points = array();
$result = mysqli_query($con, "SELECT ID,AccountID,time FROM tbhealth_temp order by time");
while ($row = mysqli_fetch_array($result)) {
$point = array("value1" => $row['time'], "value2" => $row['TempValue']);
array_push($data_points, $point);
}
echo json_encode($data_points);
}
mysqli_close($con);
?>
。有人可以帮忙吗？