45 lines
1.5 KiB
Markdown
45 lines
1.5 KiB
Markdown
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---
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title: String Length
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---
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The `length` property represents the length of a string.
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## Syntax
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str.length
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<a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length' target='_blank' rel='nofollow'>MDN link</a> | <a href='https://msdn.microsoft.com/en-us/LIBRary/3d616214%28v=vs.94%29.aspx' target='_blank' rel='nofollow'>MSDN link</a>
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## Description
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This property returns the number of code units in the string. UTF-16, the string format used by JavaScript, uses a single 16-bit code unit to represent the most common characters, but needs to use two code units for less commonly-used characters, so it's possible for the value returned by length to not match the actual number of characters in the string.
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For an empty string, length is 0.
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The static property `String.length` returns the value 1.
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## Examples
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var x = 'Mozilla';
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var empty = '';
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console.log('Mozilla is ' + x.length + ' code units long');
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/* "Mozilla is 7 code units long" */
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console.log('The empty string has a length of ' + empty.length);
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/* "The empty string has a length of 0" */
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var str = "every good boy does fine";
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var start = 0;
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var end = str.length - 1;
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var tmp = "";
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var arr = new Array(end);
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while (end >= 0) {
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arr[start++] = str.charAt(end--);
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}
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// Join the elements of the array with a
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var str2 = arr.join('');
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document.write(str2);
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// Output: enif seod yob doog yreve
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