我有2个数据帧列表。每个列表都有24个数据帧
list1 <- (data1, data2, ..., data24)
list2 <- (result1, result2, ...., result3)
我希望cbind data1与result1，data2与result2等等。然后rbin将所有数据框组合在一起：
all1 <- cbind(data1, result1)
all2 <- cbind(data2, result2)
all.in <- rbind(all1, all2)
如何有效地使用24个数据帧？
答案 0 :(得分：6)
在tidyverse语法中，<?php
session_start();
// variable declaration
$username = "";
$errors = array();
$_SESSION['success'] = "";
// connect to database
$db = mysqli_connect('localhost', 'root', '', 'registration');
// REGISTER USER
if (isset($_POST['reg_user'])) {
// receive all input values from the form
$username = mysqli_real_escape_string($db, $_POST['username']);
$password_1 = mysqli_real_escape_string($db, $_POST['password_1']);
$password_2 = mysqli_real_escape_string($db, $_POST['password_2']);
// form validation: ensure that the form is correctly filled
if (empty($username)) { array_push($errors, "Username is required"); }
if (empty($password_1)) { array_push($errors, "Password is required"); }
if ($password_1 != $password_2) {
array_push($errors, "The two passwords do not match");
}
// register user if there are no errors in the form
if (count($errors) == 0) {
$password = md5($password_1);//encrypt the password before saving in the database
$query = "INSERT INTO users (username, password)
VALUES('$username', '$password')";
mysqli_query($db, $query);
$_SESSION['username'] = $username;
$_SESSION['success'] = "You are now logged in";
header('location: index.php');
}
}
// LOGIN USER
if (isset($_POST['login_user'])) {
$username = mysqli_real_escape_string($db, $_POST['username']);
$password = mysqli_real_escape_string($db, $_POST['password']);
if (empty($username)) {
array_push($errors, "Username is required");
}
if (empty($password)) {
array_push($errors, "Password is required");
}
if (count($errors) == 0) {
$password = md5($password);
$query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
$results = mysqli_query($db, $query);
if (mysqli_num_rows($results) == 1) {
$_SESSION['username'] = $username;
$_SESSION['success'] = "You are now logged in";
header('location: index.php');
}else {
array_push($errors, "Wrong username/password combination");
}
}
}
?>
和dplyr::bind_rows会将列表绑定在一起，并由bind_cols变体调用：
purrr::map_df library(tidyverse)
l1 <- list(mtcars[1:2, 1, drop = FALSE], mtcars[3:4, 1, drop = FALSE])
l2 <- list(mtcars[1:2, 2:6], mtcars[3:4, 2:6])
map2_dfr(l1, l2, bind_cols)
#> mpg cyl disp hp drat wt
#> 1 21.0 6 160 110 3.90 2.620
#> 2 21.0 6 160 110 3.90 2.875
#> 3 22.8 4 108 93 3.85 2.320
#> 4 21.4 6 258 110 3.08 3.215
参数可以传递给.id和bind_rows，并且会生成一个新列，其中包含一个索引，每个列都有一个列表元素来自
答案 1 :(得分：5)
我可能会这样做：
l1 <- list(mtcars,mtcars)
l2 <- list(mtcars,mtcars)
do.call(rbind,mapply(FUN = cbind,l1,l2,SIMPLIFY = FALSE))
如果数据框非常大，您可以切换到cbind和rbind的dplyr或data.table等效项。