From cc43b5ebe58e1a760eea7d953451f28d9eb61d66 Mon Sep 17 00:00:00 2001
From: 8ga <jkwlstv@outlook.com>
Date: Fri, 10 Jan 2025 11:15:07 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20CharAsciiFilter.java?=
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---
 CharAsciiFilter.java | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 CharAsciiFilter.java

diff --git a/CharAsciiFilter.java b/CharAsciiFilter.java
new file mode 100644
index 0000000..9c455dc
--- /dev/null
+++ b/CharAsciiFilter.java
@@ -0,0 +1,33 @@
+public class CharAsciiFilter {
+
+    // 用最少的内存过滤出小写字母
+    static final String str = "Aa1b2c3d4e5f6f7";
+
+    // 内存开销更低
+    static void good() {
+        char[] chars = str.toCharArray();
+        int x = 0;
+        for (int i = 0; i < chars.length; i++) {
+            char c = chars[i];
+            if (c >= 97 && c <= 122) {
+                chars[x] = c;
+                x = x + 1;
+            }
+        }
+        System.out.println(new String(chars, 0, x));
+    }
+
+    // 常规解法
+    static void general() {
+        char[] chars = str.toCharArray();
+        StringBuilder sb = new StringBuilder();
+        for (char c : chars) {
+            // Character.isLetter(c)
+            if (c >= 97 && c <= 122) {
+                sb.append(c);
+            }
+        }
+        System.out.println(sb);
+    }
+
+}