Question

说我有一个像这样的对象

```
{
  "ListOfStudents": {
    "-LTzCztVLA0PW-duF-3e": {
      "StudentInfo": {
        "csvTestFile": {
          "2018-12-18": {
            "attendanceDate": "2018-12-18",
            "attendanceStatus": "present"
          },
          "2018-12-19": {
            "attendanceDate": "2018-12-19",
            "attendanceStatus": "absent"
          },
          "2018-12-20": {
            "attendanceDate": "2018-12-20",
            "attendanceStatus": "present"
          }
        }
      }
    },
    "-LTz15VLA0PW-duF-123": {
      "StudentInfo": {
        "csvTestFile": {
          "2018-12-18": {
            "attendanceDate": "2018-12-18",
            "attendanceStatus": "present"
          },
          "2018-12-19": {
            "attendanceDate": "2018-12-19",
            "attendanceStatus": "absent"
          },
          "2018-12-20": {
            "attendanceDate": "2018-12-20",
            "attendanceStatus": "absent"
          }
        }
      }
    },
    "-LTz15VL515W-duF-163": {
      "StudentInfo": {
        "csvTestFile": {
          "2018-12-18": {
            "attendanceDate": "2018-12-18",
            "attendanceStatus": "absent"
          },
          "2018-12-19": {
            "attendanceDate": "2018-12-19",
            "attendanceStatus": "absent"
          },
          "2018-12-20": {
            "attendanceDate": "2018-12-20",
            "attendanceStatus": "absent"
          }
        }
      }
    }
  }
}
```

这是我的代码

const names = 'Albert,John,Alex';

saveCSVFile(data) {
const { classUID } = data;
const { currentUser } = firebase.auth();

const student = [];

firebase
  .database()
  .ref(`/users/${currentUser.uid}/ClassAttendance/${classUID}/ListOfStudents`)
  .on('value', snapshot1 => {
    snapshot1.forEach(child => {
      student.push(child.val().StudentInfo);

      const keys = Object.keys(child.val().StudentInfo.csvTestFile);
      const dates = keys.map(key => child.val().StudentInfo.csvTestFile[key]);
      console.log(dates);
    });
  });
}

Here's the console log output

我想要的是将'attendanceStatus'合并到一个字符串中，但是对于每个第一个对象，我想在字符串中放入每个名称，对于每个最后一个对象，我都想放入 \ n'和每个出席状态的（逗号）。

预期的最终字符串输出：

'Albert，现在，不在，现在\ n

约翰，现在，不在，缺席\ n

亚历克斯，缺席，缺席，缺席\ n'

或者可能是这样的输出

“阿尔伯特，现在，缺席，现在\ n约翰，现在，缺席，缺席\ n亚历克斯，缺席，缺席，缺席\ n'

我一直在考虑如何做一个星期，但是没有运气。请帮助

Answer 1

我不确定这是否是您要的，但我希望这能使您走上正确的轨道。

2018/12/22 20:12:37 [error] 22034#22034: *81 connect() to unix:/home/user/project/shared/tmp/sockets/puma.sock failed (111: Connection refused) while connecting to upstream, client: xx.xx.xx.xx, server: localhost, request: "GET /api/v1/login HTTP/1.1", upstream: "http://unix:/home/user/project/shared/tmp/sockets/puma.sock:/500.html", host: "xx.xx.xx.xx"

Answer 2

以下是使用map的实现：

let list = {
        "-LTzCztVLA0PW-duF-3e": {
          "StudentInfo": {
            "csvTestFile": {
              "2018-12-18": {
                "attendanceDate": "2018-12-18",
                "attendanceStatus": "present"
              },
              "2018-12-19": {
                "attendanceDate": "2018-12-19",
                "attendanceStatus": "absent"
              },
              "2018-12-20": {
                "attendanceDate": "2018-12-20",
                "attendanceStatus": "present"
              }
            }
          }
        },
        "-LTz15VLA0PW-duF-123": {
          "StudentInfo": {
            "csvTestFile": {
              "2018-12-18": {
                "attendanceDate": "2018-12-18",
                "attendanceStatus": "present"
              },
              "2018-12-19": {
                "attendanceDate": "2018-12-19",
                "attendanceStatus": "absent"
              },
              "2018-12-20": {
                "attendanceDate": "2018-12-20",
                "attendanceStatus": "absent"
              }
            }
          }
        },
        "-LTz15VL515W-duF-163": {
          "StudentInfo": {
            "csvTestFile": {
              "2018-12-18": {
                "attendanceDate": "2018-12-18",
                "attendanceStatus": "absent"
              },
              "2018-12-19": {
                "attendanceDate": "2018-12-19",
                "attendanceStatus": "absent"
              },
              "2018-12-20": {
                "attendanceDate": "2018-12-20",
                "attendanceStatus": "absent"
              }
            }
          }
        }
     }
     
    const names = 'Albert,John,Alex';

    let resultString = Object.keys(list).map((l, index) => {
      let csvTestFiles = list[l].StudentInfo.csvTestFile;
      return Object.keys(csvTestFiles).map((i, innerIndex) => {
        let str = innerIndex === 0 ? `${names.split(',')[index]},` : '';
        return str + csvTestFiles[i].attendanceStatus;
      }).join(',');
    }).join('\\n').concat('\\n'); // replace with '\n' if you want the new line instead, concat is just appending last '\n' to the string
    console.log(resultString);

如何将对象合并为一个字符串

2 个答案: