Java移除中文字符代码中‘if(c>40 && c<127)’语句含义咨询

Hey there! Let's break down exactly what this condition does, especially since you're using it to filter out Chinese characters.

What the Condition Checks #

First, c here is almost certainly the Unicode code point (or char value) of the character you're evaluating. In Java, char values map directly to UTF-16 code units, which align with ASCII values for characters in the 0-127 range.

The condition c>40 && c<127 translates to:

Keep this character only if its ASCII/Unicode value is greater than 40 AND less than 127.

Breaking Down the Number Ranges #

Let's tie those numbers to actual characters:

• ASCII 40 corresponds to the left parenthesis (
• ASCII 127 is the DEL (delete) control character
• So this condition retains characters with ASCII values from 41 to 126 inclusive.

Why This Removes Chinese Characters #

Chinese characters have Unicode code points starting at U+4E00 (decimal 20013), which is way larger than 127. Any character outside the 41-126 range (including all Chinese characters) will fail this condition and get excluded/removed by your code.

Bonus: What Characters Get Kept? #

The 41-126 range includes:

• All uppercase and lowercase English letters (A-Z, a-z)
• All numeric digits (0-9)
• Most common English punctuation (like ), *, +, -, ., /, :, ;, <, =, >, ?, @, [, \, ], ^, _, `, {, |, }, ~)
• Symbols like !, ", #, $, %, &, '

Note that this condition will also filter out:

• Spaces (ASCII 32), tabs (ASCII 9), newlines (ASCII 10) — all ≤40
• Other control characters (0-31, 127)
• Non-English non-Chinese characters (like Japanese kanji, Korean hangul, accented European letters) since their code points are >127

内容的提问来源于stack exchange，提问作者Sean Stewart