Error NG0900 An error occurred while trying to compare. Only arrays and iterable objects allowed

Using *ngFor I am able to render the data but it throws this error Error: NG0900: An error occurred while trying to compare '[objectObject]'. Only arrays and iterable objects are allowed This is my service method asyncgetEditions():Promise<Observable<Cigales>>{returnthis.http.get<Ciga...

P粉226667290 2024-02-25 19:15:04 0  1  465

javascript - Vue.js uses functions to operate properties of objects in data without triggering updates

I encountered this problem when learning the Vue.js framework. In the object iteration part of list rendering, I put an object object in the data and a button element in the li element to delete the attributes corresponding to the iteration, but after clicking the button , the corresponding attribut...

淡淡烟草味 2017-05-18 10:46:34 0  1  491

javascript - What is the role of weak set in ES6?

Weak set is not iterable and cannot use for-of, keys(), values(), forEach() to traverse values. So what is its function? Is it just about storing objects?

某草草 2017-05-19 10:43:42 0  1  553

How to use java objects to represent complex json?

There is a kind of json object that needs to be used a lot, so I want to encapsulate it into an object, {code...} The current idea is to put one layer of objects and another layer of tooltip, xAxis, and series objects, but it is completely off target. It is just an auxiliary object. . Are there any ...

给我你的怀抱 2017-05-17 10:08:15 0  2  629

python - In flask-sqlalchemy, how to convert query statements into raw SQL and print them out?

Use sqlalchemy in python flask to create a table as follows: {code...} Now the query results are as follows: {code...} What is obtained is a queryset object. Is there any way to combine all the data in this object? Are all the contents printed? Instead of just getting...

世界只因有你 2017-06-12 09:26:42 0  3  1401

**Error type: Unable to iterate 'NoneType' object**

I want to use ssh tunnel to access Mysql database. Unfortunately, the architecture of this code does not seem to support my query format, as the function does not appear to be compatible with my query format. /Users/peter/PycharmProjects/MySqlLocalhostTest/venv/lib/python3.10/site-packages/paramiko/...

P粉141035089 2024-04-06 10:26:38 0  1  538

How to find JSON data based on other content in a JSON object when duplicates exist?

I'm currently implementing some data charts on a website, and I have a JSON that contains some data, specifically some ID numbers, some dates, and some data points. Because I have multiple dates under the same ID, I'm looking for a way to do essentially "find a JSON object with this ID and mont...

P粉713846879 2024-04-04 10:57:45 0  1  556

Convert Vue array to proxy object

I'm new to Vue. While making this component, I ran into difficulty here. I use the following code to make an AJAX request to an API that returns an array: importaxiosfrom'axios';exportdefault{data(){return{tickets:[],};},methods:{getTickets(){axios.get(url ).then((response)=>{console.log(re

P粉476046165 2023-09-16 19:32:12 0  2  576

A usage in python is unclear

In the process of writing a crawler in Python (crawling Wikipedia entries), the url["href"] appeared during the output process of using the iterator. I thought it should belong to a usage in the iterator, but I couldn't find it. Please help me with this usage. I mean, thank you for the url...

阿神 2017-05-18 10:59:46 0  1  789

javascript - Problem with promises received by await in async/await

In async/await, what await needs to receive is a promise object, so I write like this: {code...} {code...} This is no problem. AreaSvr.getList returns a promise object. Now I encapsulate AreaSvr.getList and add a cache: {Code...

曾经蜡笔没有小新 2017-05-16 13:38:44 0  2  801

angular.js - Has anyone read the book Learn and Use Angular Instantly?

The code is as shown in the picture. The book says that ng-repeat can act on objects. If it acts on objects, the HTML rendering result will make Misko starting with a capital letter come first. The code results mentioned in the book are Misko, brad, and shyma. But the result of the code I typed is s...

習慣沉默 2017-05-15 17:02:43 0  1  580

mysql - Database design (scheme design), should NULL be avoided as much as possible?

I learned the actual phenomenon: NULL has unclear semantics and is not easy to optimize when querying. If it represents a null value, there can be other alternatives (logically) VARCHAR(100) NOT NULL DEFAULT ''; INT NOT NULL DEFAULT 0; I hope you can understand the expected phenomenon. When designin...

仅有的幸福 2017-05-18 10:54:25 0  2  729

In Gao Qi's Java video code, why does the time print out using a new object created using the Date class, but the hash code address prints out using a self-created object?

Recently, when watching Teacher Gao's video, I found a knowledge point that I didn't quite understand. The code is as follows: {Code...} The output result is as follows: {Code...} It also prints an object. Why does the Date class object output the current time, but since What about creating an objec...

巴扎黑 2017-06-23 09:14:34 0  4  971

javascript - Ask a question about this in JS.

Why is the onclick event not triggered in this place? If you can get the DOM object of the currently clicked li in jquery, can't it be used in JS like this? {Code...} {Code...} Modification: {Code...} {Code...} Thank you all, I used jquery before, now I will read it again...

滿天的星座 2017-07-05 10:49:51 0  7  844

javascript - Use vue.js to achieve the effect: click li, get the html value of the current click li, and the parameter this becomes the window object?

The effect to be achieved: Click li to get the html value of the currently clicked li; Main code {code...} Problem description: The this passed after clicking li is printed as the window object, not the li object, so the object cannot be found ;How to pass the current li object to js?

曾经蜡笔没有小新 2017-06-14 10:54:14 0  4  983

How to execute Promise repeatedly in async function?

I'm learning promises and asyncawait, here I want to call the addPost function and push an object twice, then I want to loop through the object array to see the results, but in this code the results are not as expected. Here, when the code executes to the showDetails() function, it only shows 3 obje...

P粉356128676 2023-08-18 14:54:42 0  2  448

php - Anonymous function return value problem

{Code...} {Code...} My question is whether passing in any object converts the closure object into the original object? Why is this happening? I asked in /a/11... Why do I pass in any object? Enter ($this) to retrieve the original object.

phpcn_u1582 2017-05-16 12:02:57 0  2  638