Why are dot notations used

If you call a method or function using the parentheses, the interpreter assumes that you want to run the function or method. If you call a method or function without parentheses, the interpreter assumes that you want to return the function or method. For a list of the methods of an object, type dir obj where obj is the object name list, str, int , or any object of the type , i.

What about. If you print the result of a print statement, the inner print statement will still executed, and then you get None because that inner print statement returned nothing technically, it returned None to the outer print function.

That would also be correct. Also, instead of writing len "hello" I could write "hello". Test it out. Instead, it creates a list of strings.

It just creates a string that is a chain of all its arguments, separated by the given separator. The short and simple answer is that what I stated is a rule of thumb. Dot notation is much easier to read than bracket notation and is therefor used more often.

You can access properties on an object by specifying the name of the object followed by the property name in brackets. But bracket notation is also useful when working with Objects. When working with bracket notation, property identifiers only have to be a String.

They can include any characters, including spaces. Variables may also be used as long as the variable resolves to a String. This means there are fewer limitations when working with bracket notation. We can now have spaces in our strings, and can even start strings with numbers. Perhaps most importantly, we can now use variables to access properties in an object.

Take a look at this variable example. It might be a little confusing at first, so bear with me:. Thus, meow is logged to the console. Attempting to lookup obj. This outputs 'value' , since 1 is coerced into '1'.

This also outputs 'value' , since both foo and bar are converted to the same string. A method is not bound to the object that it is a method of. Specifically, this is not fixed in a method. Put another way, this does not necessarily refer to the object containing a method.

Instead, this is "passed" by the function call. See method binding. Could you elaborate more on array. You say that properties accessed by dot notation are not evaluated so in case of array. The elements in an array are stored in properties this is what confuses me. What do you mean by stored in properties?

What are properties? In my understanding array is just bunch of values without properties. This answer is particularly valuable because it explains the difference between the two notations. The simple fix for that is to switch to bracket notation: app. Benjamin Crouzier Benjamin Crouzier Helpful answer.

Thank You. Works on chrome res. CdB CdB 4, 6 6 gold badges 43 43 silver badges 67 67 bronze badges. In IE : window['parent']['func'] is not equivalent to window. You have to use square bracket notation when - The property name is number. Jason Roman 7, 10 10 gold badges 32 32 silver badges 36 36 bronze badges. Belhadjer Samir Belhadjer Samir 1, 4 4 silver badges 13 13 bronze badges. Because of evaluation, could the bracket notation be slower?

Bracket notation can use variables, so it is useful in two instances where dot notation will not work: 1 When the property names are dynamically determined when the exact names are not known until runtime. Lev Stefanovich Lev Stefanovich 6 6 bronze badges. Anshul Anshul 8, 9 9 gold badges 56 56 silver badges 72 72 bronze badges.

And there are also situations where the bracket notation is not allowed at all, even if you don't have dashes. For instance, you can write Math. Manish Waran Manish Waran 60 9 9 bronze badges.

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