In this example, we get exponential notation when the fraction is not small enough: > 0.003. However, toExponential() does display an exponent: > 1234.toString() In this example, the magnitude of the number is not large enough for an exponent being displayed by toString(). Remember, that only the first number in the string will be returned. parseInt will return an integer found in the beginning of the string. The first argument of parseInt must be a string. Results are mixed, because we reach the limits of the precision that can be achieved when converting binary numbers to a decimal notation: > 1234567890123456789012.toString() Use parseInt () function, which parses a string and returns an integer. In this example, we force more precision when toString() would also use exponential notation. If it is omitted, then as many significant digits are included as necessary to uniquely specify the number. fractionDigits is a number between 0 and 20 that determines how many digits should be shown after the decimal point. (fractionDigits?) forces a number to be expressed in exponential notation. The last example gives us hope that we might be able to use parseInt() for converting numbers to integers. However, most of the features Fraction. Thus, it is best to always explicitly state the radix, to always call parseInt() with two arguments.ĭon’t use parseInt() to convert a number to an integer. Of course, there already exists a library that implements fractions beautifully in JavaScript - Fraction.js, which would be very useful for general purposes. Additionally, some engines set the radix to 8 if str starts with a zero: > parseInt('010') ![]() So far I have described the behavior of parseInt() according to the ECMAScript specification. Given that JavaScript is mainly used for client-side scripting within modern web browsers, and that almost all Web browsers provide the alert function, alert. If radix is already 16, then the hexadecimal prefix is optional: > parseInt('0xA', 16) If radix is missing, then it is assumed to be 10, except if str begins with “0x” or “0X,” in which case radix is set to 16 (hexadecimal): > parseInt('0xA') ![]() If the radix is greater than 10, letters are used as digits (case-insensitively), in addition to 0–9. It determines the base of the number to be parsed. The range of the radix is 2 ≤ radix ≤ 36. Convert a number to a fraction in JavaScript Raw convert-number-to-fraction.js / Converts numbers to fractions: - 1. As noted in Section 7.11, “Details of comparison predicates”: Note that this behavior is dictated by IEEE 754. Thus, it is best to combine isNaN with a type check: function myIsNaN ( value ) That conversion can produce NaN and then the function incorrectly returns true: > isNaN('xyz') ![]() However, isNaN does not work properly with nonnumbers, because it first converts those to numbers. If you want to check whether a value is NaN, you have to use the global function isNaN(): > isNaN(NaN) You therefore can’t search for NaN in an array via that method: >. NaN is the only value that is not equal to itself: > NaN = NaN
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