How basic data types compare across common programming languages. See the Developer Tools guides for related tools and explanations.
| Concept | JavaScript | Python | Java |
|---|---|---|---|
| Whole/decimal number | Number (one type for both) | int / float | int / double |
| Text | String | str | String |
| True/false | Boolean | bool | boolean |
| Ordered list | Array | list | ArrayList |
| Key-value pairs | Object | dict | HashMap |
| Absence of a value | null / undefined | None | null |
See all Developer Tools for working with data across formats and languages.
Developer Tools
JavaScript represents all numbers, whole and decimal, using the same 64-bit floating-point format, unlike languages that separate int and float into distinct types.
Conventions vary. JavaScript uses undefined for a variable that hasn’t been assigned and null for an intentional absence of value. Python uses a single None for both cases.
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