Question

聚合后，我得到了这个结果，

{
    "date" : ISODate("2017-08-30T00:00:00.000Z"),
    "unknown" : 365,
    "male" : 2
}

是否可以将其转换为以下格式

$unwind

尝试使用$project和from PyQt5 import QtCore, QtWidgets from PyQt5.QtWidgets import QMessageBox class Ui_form(object): def setupUi(self, form): form.setObjectName("form") form.resize(1000, 650) self.groupBox = QtWidgets.QGroupBox(form) self.groupBox.setGeometry(QtCore.QRect(530, 350, 451, 281)) self.groupBox.setObjectName("groupBox") self.stackedWidget = QtWidgets.QStackedWidget(self.groupBox) self.stackedWidget.setGeometry(QtCore.QRect(9, 19, 431, 241)) self.stackedWidget.setObjectName("stackedWidget") self.page_1 = QtWidgets.QWidget() self.page_1.setObjectName("page_1") self.login_button = QtWidgets.QPushButton(self.page_1) self.login_button.setGeometry(QtCore.QRect(20, 210, 75, 23)) self.login_button.setObjectName("login_button") self.register_button = QtWidgets.QPushButton(self.page_1) self.register_button.setGeometry(QtCore.QRect(180, 210, 75, 23)) self.register_button.setObjectName("register_button") self.exit_button = QtWidgets.QPushButton(self.page_1) self.exit_button.setGeometry(QtCore.QRect(330, 210, 75, 23)) self.exit_button.setObjectName("exit_button") self.username_line = QtWidgets.QLineEdit(self.page_1) self.username_line.setGeometry(QtCore.QRect(230, 40, 113, 20)) self.username_line.setObjectName("username_line") self.password_line = QtWidgets.QLineEdit(self.page_1) self.password_line.setGeometry(QtCore.QRect(230, 110, 113, 20)) self.password_line.setObjectName("password_line") self.username_label = QtWidgets.QLabel(self.page_1) self.username_label.setGeometry(QtCore.QRect(60, 40, 81, 16)) self.username_label.setObjectName("username_label") self.password_label = QtWidgets.QLabel(self.page_1) self.password_label.setGeometry(QtCore.QRect(60, 110, 61, 16)) self.password_label.setObjectName("password_label") self.stackedWidget.addWidget(self.page_1) self.page_2 = QtWidgets.QWidget() self.page_2.setObjectName("page_2") self.registeruser_label = QtWidgets.QLabel(self.page_2) self.registeruser_label.setGeometry(QtCore.QRect(60, 33, 71, 20)) self.registeruser_label.setObjectName("registeruser_label") self.registerepass_label = QtWidgets.QLabel(self.page_2) self.registerepass_label.setGeometry(QtCore.QRect(60, 100, 61, 16)) self.registerepass_label.setObjectName("registerepass_label") self.registeruser_line = QtWidgets.QLineEdit(self.page_2) self.registeruser_line.setGeometry(QtCore.QRect(240, 40, 113, 20)) self.registeruser_line.setObjectName("registeruser_line") self.registerpass_line = QtWidgets.QLineEdit(self.page_2) self.registerpass_line.setGeometry(QtCore.QRect(240, 100, 113, 20)) self.registerpass_line.setObjectName("registerpass_line") self.signup_button = QtWidgets.QPushButton(self.page_2) self.signup_button.setGeometry(QtCore.QRect(70, 190, 75, 23)) self.signup_button.setObjectName("signup_button") self.cancel_button = QtWidgets.QPushButton(self.page_2) self.cancel_button.setGeometry(QtCore.QRect(270, 190, 75, 23)) self.cancel_button.setObjectName("cancel_button") self.stackedWidget.addWidget(self.page_2) self.retranslateUi(form) self.stackedWidget.setCurrentIndex(0) self.login_button.clicked.connect(self.login_button_clicked) self.register_button.clicked.connect(self.register_button_clicked) self.cancel_button.clicked.connect(self.cancel_button_clicked) self.exit_button.clicked.connect(self.exit_button_clicked) def retranslateUi(self, form): _translate = QtCore.QCoreApplication.translate form.setWindowTitle(_translate("form", "Form")) self.groupBox.setTitle(_translate("form", "USER")) self.login_button.setText(_translate("form", "LOG IN")) self.register_button.setText(_translate("form", "REGISTER")) self.exit_button.setText(_translate("form", "EXIT")) self.username_label.setText(_translate("form", "USERNAME")) self.password_label.setText(_translate("form", "PASSWORD")) self.registeruser_label.setText(_translate("form", "USERNAME")) self.registerepass_label.setText(_translate("form", "PASSWORD")) self.signup_button.setText(_translate("form", "SIGN UP")) self.cancel_button.setText(_translate("form", "CANCEL")) def login_button_clicked(self): file = open('user.txt','r') for line in file: us, pa = line.rstrip().split(';') if self.username_line.text() == us and self.password_line.text() == pa: QMessageBox.information(QMessageBox(), "Login", "LOGIN SUCCESS!") break else: QMessageBox.information(QMessageBox(), "login", "LOGIN FAILED!") def register_button_clicked(self): self.stackedWidget.setCurrentIndex(1) def cancel_button_clicked(self): self.stackedWidget.setCurrentIndex(-1) def exit_button_clicked(self): self.close() if __name__ == '__main__': import sys app = QtWidgets.QApplication(sys.argv) LOGIN_window = QtWidgets.QDialog() LOGIN = Ui_form() LOGIN.setupUi(LOGIN_window) LOGIN_window.show() sys.exit(app.exec_())，但无法将数组对象转换为键值对

Answer 1

是的，使用$arrayToObject和$map将现有数组转换为它接受的格式：

db.collection.aggregate([
  { "$replaceRoot": {
    "newRoot": {
      "$arrayToObject": {
        "$concatArrays": [
          [{ "k": "date", "v": "$_id.date" }],  
          { "$map": {
            "input": "$aggr",
            "in": { "k": "$$this.gender", "v": "$$this.count" }
          }}
        ]
      }
    }    
  }}
])

当然，如果这实际上只是在＆＃34;尾巴＆＃34;对于现有聚合而言，您至少没有引入运算符的MongoDB 3.4.4，那么您只需将结果重新整形为客户端代码：

db.collection.aggregate([
  // existing pipeline
]).map(d => 
  Object.assign(
    { date: d._id.date },
    d.aggr.reduce((acc,curr) =>
      Object.assign(acc,{ [curr.gender]: curr.count }),{}
    )
  )
)

将对象项目数组转换为键值

1 个答案: