JavaScript Basics -3 JavaScript data types, data type conversions

First, the data type

Data type

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Basic type

-Number Type

-can represent either a 32-bit integer or a 64-bit floating-point number

-Integer

-Decimal: A whole number of ten-in-one, such as 1234567890

-Eight binary: every eight into an integer, such as 01235670

-16 binary:

-Floating point number

-Use decimal point to record data, such as 95.5,3.1415926

-Use index to record data, such as 4.3e23, 4.3E-23

String type

-String type

-Represents a series of text character data, such as gender, name, address, etc.

-sequences consisting of Unicode characters, numbers, punctuation

-JavaScript does not strictly differentiate between character and string types as in the Java language

-a pair of single or double quotation marks

-special characters require escape character

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Boolean type

-Boolean type

-Only two values: True and False

-also represents 1 and 0

-True=1,false=0 in the actual operation

Undefined

-Undefined

-Semantics: The data does not exist

-A variable was declared but never assigned, or the object property does not exist

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Ii. Conversion of data types

Implicit conversions

-JavaScript is loosely typed programming language

-the variable does not need to specify a data type when declaring

-variables are determined by the assignment operation data type

-Different types of data are automatically converted during the calculation

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Data type Conversion Functions

-ToString ()

-Convert to string, all data types can be converted to string type

-parseint ()

-resolves an integer part of a string or number

-Returns Nan (not a number) if there is no part to convert

-Parsefloat ()

-Resolves a string's floating-point number part

-Returns Nan if there are no parts that can be converted

-Number ()

-Parse a string into number

-Returns Nan if illegal characters are included

Summary: This chapter covers JavaScript data types, data type conversions

This article from the "Technical Exchange" blog, declined reprint!

JavaScript Basics -3 JavaScript data types, data type conversions