'e' in javascript numbers

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误落风尘
误落风尘 2021-02-20 18:20

I need to understand the following:

when I type 4e4 in Google Chrome\'s console it returns 40000.

Can anyone help me to understand what

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  • 2021-02-20 18:54

    4e4 is a floating-point number representation. It consists of:

    1. Sign - S(+ or -)
    2. Mantissa - M(some number, normalized: 1.x where x is some sequence of digits)
    3. Exponent - E(represents a power of 10 that is Mantissa(M) multiplied with)

    It is also a way of how floating-point numbers are stored on the system. For instance, for single-precision we get: single-precision floating-point number representation

    Together, it gives us:

    -1^S * M * p^E where p is the basis of the numerical system

    So, in common sense, p can be anything so that 4e4 could be also 4 * 5^4 if p == 5

    As we usually work with decimal values p is equal to 10

    And as was answered before, 4e4 == 4 * 10^4 (as 4 is a decimal value in this case)

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  • 2021-02-20 19:05

    4*10^4

    if it was 4e5 would be = 4*10^5

    etc

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  • 2021-02-20 19:15

    'e' in a number like that is the same as 'times 10 to the power of'

    3.2e6 is 3.2x10^6

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