02 2022 档案
摘要：网上搜索到“[\u4e00-\u9fa5]”匹配所有中文字符，实际测试结果是把数字、英文、中文全部匹配了，不知道怎么回事，百度搜索到的匹配中文字符方法都是这样的。 于是去翻舍得的正则表达式实用教程，原来是这么简单！ “[[:unicode:]]” （不含分号）就可以匹配中文字符了！在此感谢舍得！ [
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摘要：正则表达式26英文字母大小写互转 查找： [a-z] 或 [A-Za-z] 说明：可以不分大小写 小写转大写替换： \u\0 大写转小写替换： \L\0 \u\0 小写转大写命令，U和u都一样 \L\0 大写转小写命令， -u, uppercase -l, lowercase
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摘要：If the case of a compile-time constant, the compiler is allowed to "fold" the constant value into any calculations in which it's used; that is, the ca
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摘要：Inheritance doesn't just copy the interface of the base class. When you create an object of the derived class, it contains within it a subobject of th
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摘要：You can create a main() for each one of your classes; this technique of putting a main() in each class allows easy testing for each class. Even if you
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摘要：Access control is often referred to as implementation hiding. Wrapping data and methods within classes in combination with implemetation hiding is oft
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摘要：If you created a new package and inherit from a class in another package, the only members you have access to are the public members of the original p
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摘要：The private keyword means that no one can access the member except the class that contains that member, inside methods of that class.
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摘要：Note that compiled code is often placed in a different directory than source code, but the path to the compiled code must still be found by the JVM us
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摘要：When you create a source-code file for Java, it's commonly called a compilation unit(sometimes a translation unit). Each compilation unit must have a
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摘要：Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper class. List<Int
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摘要：Resurcion The usual method is to make the recursive call part of an if statement. Wtih luck or foresight, tesst eventually becomes false, and the chai
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摘要：The public keyword means that the method is available to the outside world.
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摘要：静态主方法只能访问静态变量， 如果要访问动态变量，必须将变量实例化。 在JAVA程序中，除了主静态方法以及类方法之外，其他在该类下定义的实例变量、实例方法，在主类方法中调用时必须要将其实例化，就是要加上对象的引用。 Ordinarily, when you create a class you ar
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摘要：str = "I love everyone!"chars = str.split(' ')print(chars)ls_str= list(str)str2 = "".join(ls_str)print(str2)
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摘要：Repetition qualifiers (*, +, ?, {m,n}, etc) cannot be directly nested. This avoids ambiguity with the non-greedy modifier suffix ?, and with other mod
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摘要：An array is simply a sequence of either objects or primitives that are all the same type and are packaged together under one identifier name. int[] a1
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摘要：ctrl + 鼠标左键 就可以快速进入详情
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