我的数据框如下：
dput(Moment[1:15,])
structure(list(SectionCut = c("1", "1", "1", "1", "2", "2", "2",
"2", "3", "3", "3", "3", "Left", "Left", "Left"), N_l = c("1",
"2", "3", "4", "1", "2", "3", "4", "1", "2", "3", "4", "1", "2",
"3"), UG = c("84", "84", "84", "84", "84", "84", "84", "84",
"84", "84", "84", "84", "84", "84", "84"), S = c("12", "12",
"12", "12", "12", "12", "12", "12", "12", "12", "12", "12", "12",
"12", "12"), Sample = c("S00", "S00", "S00", "S00", "S00", "S00",
"S00", "S00", "S00", "S00", "S00", "S00", "S00", "S00", "S00"
), DF = c(0.367164093630677, 0.540130283330855, 0.590662743113521,
0.497030982705986, 0.000319303760901125, 0.000504925126205843,
0.00051127115578891, 0.000395434233037301, 0.413218926236695,
0.610726262711904, 0.685000816613652, 0.59474035159783, 0.483354599644366,
0.645710184115934, 0.625883097885242)), row.names = c(NA, -15L
), class = c("tbl_df", "tbl", "data.frame"))
我想通过旋转SectionCut列来分离列的内容。我基本上希望以某种方式使用pivot_longer的反面...因此，最后，DF列中的值将显示在5个不同的列下（SectionCut = c("1", "2", "3", "left", "right")
答案 0 :(得分：1)
在使用#include <iostream>
using namespace std;
class A {
public:
string value;
A() {
value = "ABC";
}
void print_values() {
std::cout << "value: " << value << std::endl;
}
};
class B {
A& a_prop;
public:
B(A& a) : a_prop(a) {
}
void print_values() {
a_prop.print_values();
}
};
int main() {
auto objectA = std::make_unique<A>();
auto objectB = std::make_unique<B>(*objectA);
objectA->value.replace(objectA->value.begin(), objectA->value.end() - 1, "ED");
objectA->print_values(); // Will display "EDC"
objectB->print_values(); // Will display "EDC"
auto objectAMoved = std::move(objectA);
objectAMoved->print_values(); // Will display "EDC"
objectAMoved->value.replace(objectAMoved->value.begin(), objectAMoved->value.end() - 1, "FG");
objectB->print_values(); // Will display "FGC"
objectAMoved->print_values(); // Will display "FGC"
if (objectA == nullptr) {
cout << "A is nullptr" << endl;
} else {
objectA->print_values(); // This will cause segmentation fault segmentation fault
}
}
创建序列列之后，我们可以使用import { useState, useEffect } from 'react';
import { firestore } from '../firebase/firebase';
const useFirestore = (collection) => {
const [docs, setDocs] = useState([]);
useEffect(() => {
const unsub = firestore.collection(collection)
.orderBy('createdAt', 'desc')
.onSnapshot(snap => {
let documents = [];
snap.forEach(doc => {
documents.push({...doc.data(), id: doc.id});
});
setDocs(documents);
});
return () => unsub();
// this is a cleanup function that react will run when
// a component using the hook unmounts
}, [collection]);
return { docs };
}
export default useFirestore
中的import * as firebase from "firebase/app"
import "firebase/firestore"
const firebaseConfig = {
"this is filled with info I got from firebase just dont want to post it on the internet."
};
const firestore = firebase.initializeApp(firebaseConfig);
export { firestore }
pivot_wider-输出
tidyr