How do i convert scientific notation into number in matlab

Question

Jasmeet Kaur 2016-8-10

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https://ww2.mathworks.cn/matlabcentral/answers/299091-how-do-i-convert-scientific-notation-into-number-in-matlab

评论： Walter Roberson 2020-9-11

a=9.22222e+15

I need to convert this number and want to save the answer in variable

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Stephen23 2016-8-10

编辑：Stephen23 2016-8-10

"I need to convert this number"

what do you want to convert to:

a string
another numeric class
something else... ?

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Answer 1

Stephen23 2016-8-10

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https://ww2.mathworks.cn/matlabcentral/answers/299091-how-do-i-convert-scientific-notation-into-number-in-matlab#answer_231354

编辑：Stephen23 2016-8-10

在 MATLAB Online 中打开

The variable a is already a numeric:

>> a = 9.22222e+15
a = 9.2222e+015
>> isnumeric(a) %check that it is a numeric
ans =          1
>> fprintf('%.0f\n',a)
9222220000000000

Why do you think that it is not a numeric ? You might like to read about the different format options, which control how numeric values are displayed in MATLAB:

http://www.mathworks.com/help/matlab/ref/format.html

Remember that how a numeric value is displayed is a totally different matter to how it is stored. For example, here are three different ways of displaying your numeric value:

>> format bank
>> a = 9.22222e+15
a =  9222220000000000.00
>> format hex
>> a = 9.22222e+15
a = 434061c7b591fc00
>> format longg
>> a = 9.22222e+15
a =         9.22222e+015

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Stephen23 2016-8-10

编辑：Stephen23 2016-8-10

在 MATLAB Online 中打开

@Jasmeet Kaur: so far I have shown you that a is a variable, and that it is numeric.

Can you please explain to me why you think that a is not a variable, and why you think think that a is not numeric. I suspect that you are getting confused between displaying a numeric value and the stored numeric value (i.e. a variable): storing and displaying numeric values are two totally different things. The variable that you have created is numeric, by the standard meaning of the word in MATLAB:

a = 9.22222e+15

MATLAB, like most programming languages, does not store numeric values as "decimal" but as binary, so I have no idea what you mean by "I want covert the value of a in decimal form". The value is stored as the closest binary representation of the number that you have given, which is the best that we can do unless we get into more complicated numeric formats. And of course you can display that value in many different ways, including some that you might call "decimal": I showed you some of different ways to change the format, did you try ?

These are such basic concepts that you really should start to learn MATLAB by doing the introductory tutorials:

http://www.mathworks.com/help/matlab/getting-started-with-matlab.html

Walter Roberson 2017-9-13

Mitchell, please use https://www.mathworks.com/matlabcentral/fileexchange/22239-num2strexact--exact-version-of-num2str-

Stephen23 2017-9-13

编辑：Stephen23 2017-9-13

在 MATLAB Online 中打开

"MATLAB understand a value such as 1.0400e+4 as the whole number 10400 that it is, instead of as a non-whole number."

It certainly looks like a whole number:

>> sprintf('%.30f',1.0400e+4)
ans =
10400.000000000000000000000000000000
>> rem(1.0400e+4,1)==0
ans =
     1

How would you expect it to be different from this?

"I believe what Jasmeet was asking is..."

Jasmeet did not mention "integer" or "whole" anywhere, and gave an example value that is slightly higher than flintmax, making the output value rather meaningless in terms of "whole number or not". If that is what Jasmeet and yourself are asking about then the solution is to learn about the properties of floating point numbers

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Answer 2

Anish Vaidya 2017-11-26

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编辑：Anish Vaidya 2017-11-26

Even, I've the same problem. I want to store a number in a variable in decimal notation and then convert to array of characters.

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Walter Roberson 2017-11-26

What form is the value in at present?

When you convert it to character, how many decimal places of precision do you need?

What is the range of values possible?

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Answer 3

Surama Biswas 2020-9-11

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Following example by Stephen Cobeldick works for me. I need to place each bit by last fprintf in an array. Please help me. Thanks in advance.

>> a = 9.22222e+15

a = 9.2222e+015

>> isnumeric(a) %check that it is a numeric

ans = 1

>> fprintf('%.0f\n',a)

9222220000000000

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Walter Roberson 2020-9-11

在 MATLAB Online 中打开

b = sprintf('%.0f', a)

Walter Roberson 2020-9-11

Note that the result would be a character vector.

If the task is to store numeric 9222220000000000 as a double precision variable, then a = 9.22222e+15 already does that. The way that a variable displays is not the same thing as the value stored in the variable.

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