What freq[character]++ represents? Thanks

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I know it's simple answer but can't understand what that freq[caracter] is? And how it can be incremented if it's a string. Please be detailed

What I have tried:

function getFrequency(string) {
var freq = {};
for (var i=0; i<string.length;i++) {
var character = string.charAt(i);
if (freq[character]) {
freq[character]++;
} else {
freq[character] = 1;
}
}

return freq;
};

Posted 8-Jul-17 11:41am

Marko Djordjevic

Updated 10-Jul-17 8:58am

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Patrice T · Answer 1 · 2017-07-08T12:19:00

Quote:
And how it can be incremented if it's a string.

The fact it is not a string may help. freq() is an array.
Use the debugger, debugging is not its main purpose, the debugger allow to execute the code step by step and to inspect variables between each step. it will show you that freq() is an array that count how many times each char appeazr in the string.

There is a tool that allow you to see what your code is doing, its name is debugger. It is also a great learning tool because it show you reality and you can see which expectation match reality.
When you don't understand what your code is doing or why it does what it does, the answer is debugger.
Use the debugger to see what your code is doing. Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]
JavaScript Debugging[^]
Chrome DevTools | Web | Google Developers[^]
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't find bugs, it just help you to. When the code don't do what is expected, you are close to a bug.

Richard Deeming · Answer 2 · 2017-07-10T08:58:00

freq is an object: Working with objects - JavaScript | MDN[^]

Objects have properties. In Javascript, there are two ways to access properties. By name:

var x = someObj.myProperty;
someObj.otherProperty = 42;

Or by index:

var x = someObj['myProperty'];
someObj['otherProperty'] = 42;

Using the index is particularly useful if you don't know the name of the property until runtime.

If the specified property has not been defined, then it will return undefined. The if condition is making use of one of the uglier areas of Javascript - "truthy" and "falsy" values:
Truthy and Falsy: When All is Not Equal in JavaScript — SitePoint[^]

This could be rewritten to make use of the hasOwnProperty method[^], which might make the code slightly clearer, albeit more verbose:

if (freq.hasOwnProperty(character)){

If the specified property doesn't exist, you initialize it to the number 1.

Which is why, on subsequent iterations of the loop when the property does exist, you are able to increment it.

What freq[character]++ represents? Thanks

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