空白字符

What is Whitespace?

Whitespace refers to any character that represents horizontal or vertical blank space without producing a visible mark. The term covers a wide family of characters — from the ordinary space (U+0020) you type with the spacebar, to tab, newline, carriage return, and a rich set of Unicode-specific space characters with precise typographic widths.

In text processing, whitespace characters are fundamental delimiters. In typography, different whitespace characters carry specific semantic meanings about the size and nature of the blank space they represent.

The Unicode Whitespace Family

Unicode defines approximately 25 characters with whitespace properties. The most important are:

Control Characters vs. Space Characters

Whitespace splits into two categories: - Space characters: primarily horizontal, create horizontal gaps - Control characters: include line terminators (LF, CR, CRLF, LS, PS) that break lines and create vertical space

Line separator (U+2028) and paragraph separator (U+2029) are Unicode-specific line terminators that some parsers recognize. JavaScript template literals, for example, treat both as newlines.

Whitespace in Programming

Whitespace handling varies significantly across languages and contexts:

# Python: indentation is syntax
if True:
    print("This indent matters")

# Python string whitespace
import re
text = "hello\u2003world"          # em space
re.split(r'\s+', text)             # ['hello', 'world'] — \s matches em space
text.split(' ')                    # ['hello\u2003world'] — only splits on U+0020

// JavaScript: \s in regex matches all Unicode whitespace
/\s/.test('\u2003')   // true — em space
/\s/.test('\u3000')   // true — ideographic space

/* CSS white-space property controls whitespace rendering */
p { white-space: normal; }    /* collapse and wrap (default) */
p { white-space: pre; }       /* preserve all whitespace */
p { white-space: nowrap; }    /* no line wrapping */
p { white-space: pre-wrap; }  /* preserve, but allow wrapping */

Ideographic Space in CJK Typography

The ideographic space (U+3000,　) is a full-width space used in Chinese, Japanese, and Korean text. Its width matches a full CJK character (one em in a monospace CJK context). It is visually distinct from a standard space and matters for alignment in vertically set or grid-aligned CJK typography.

Quick Facts