var str = '0.25';
How to convert the above to 0.25?
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user198729
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`parseInt` is blazing fast, but if you need decimals, you should go with `parseFloat`: https://jsbench.me/pokty2hchw/1 – Xairoo Sep 24 '21 at 08:03
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`'0.25'*1` is about 98% faster than `parseFloat()` https://jsbench.me/bflb5lcqpw/1 – Miro Dec 01 '22 at 21:32
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1@Miro beware benchmarks against trivial single-value cases. The methods don't scale the same. Performing the same comparison on an array of 10 values at once, `parseFloat()` performs about 15% better than `''*1`: https://jsbench.me/c8ldyhrth3/1 – Will Feb 10 '23 at 12:18
4 Answers
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There are several ways to achieve it:
Using the unary plus operator:
var n = +str;
The Number constructor:
var n = Number(str);
The parseFloat function:
var n = parseFloat(str);
Christian C. Salvadó
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For your case, just use:
var str = '0.25';
var num = +str;
There are some ways to convert string to number in javascript.
The best way:
var num = +str;
It's simple enough and work with both int and float
num will be NaN if the str cannot be parsed to a valid number
You also can:
var num = Number(str); //without new. work with both int and float
or
var num = parseInt(str,10); //for integer number
var num = parseFloat(str); //for float number
DO NOT:
var num = new Number(str); //num will be an object. (typeof num == 'object') will be true.
Use parseInt only for special case, for example
var str = "ff";
var num = parseInt(str,16); //255
var str = "0xff";
var num = parseInt(str); //255
cuixiping
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