How do I find the index of an object?

How do I find the index of an object?

To find the index of an object in an array, by a specific property:

  1. Use the map() method to iterate over the array, returning only the value of the relevant property.
  2. Call the indexOf() method on the returned from map array.
  3. The indexOf method returns the index of the first occurrence of a value in an array.

How do you select the first property of an object?

To access the first property of an object, pass the object to the Object. values method and access the element at index 0 , e.g. Object. values(obj)[0] .

How do you find the first value of a object?

Use object. keys(objectName) method to get access to all the keys of object. Now, we can use indexing like Object. keys(objectName)[0] to get the key of first element of object.

Can you index an object in JavaScript?

Get a Value of an Object by Index # To get a value of an object by index, call the Object. values() method to get an array of the object’s values and use bracket notation to access the value at the specific index, e.g. Object. values(obj)[1] .

What is indexOf method in JavaScript?

JavaScript String indexOf() The indexOf() method returns the position of the first occurrence of a value in a string. The indexOf() method returns -1 if the value is not found. The indexOf() method is case sensitive.

What is the difference between findIndex and indexOf?

findIndex – Returns the index of the first element in the array where predicate is true, and -1 otherwise. indexOf – Returns the index of the first occurrence of a value in an array.

How do I find the first element of a list?

To access the first element (12) of a list, we can use the subscript syntax [ ] by passing an index 0 . In Python lists are zero-indexed, so the first element is available at index 0 . Similarly, we can also use the slicing syntax [:1] to get the first element of a list in Python.

What is object method in JavaScript?

Objects in JavaScript are collections of key/value pairs. The values can consist of properties and methods, and may contain all other JavaScript data types, such as strings, numbers, and Booleans. All objects in JavaScript descend from the parent Object constructor.

What is the starting index of an array?

So array index starts from 0 as initially i is 0 which means the first element of the array.

How do you find the first index of a substring in a given string?

To find the index of first occurrence of a substring in a string you can use String. indexOf() function. A string, say str2 , can occur in another string, say str1 , n number of times. There could be a requirement in your Java application, that you have to find the position of the first occurrence of str2 in str1 .

How does indexOf work?

indexOf() function finds the index of the first occurrence of the argument string in the given string. The value returned is 0-based. Also, it returns -1 if the value to search for never occurs. The first argument, searchValue is the string that is to be searched in the base string.