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添加两个数字 统计单词数量 反转字符串 数组元素求和 将字符串转换为数组 排序数组 求数组平均值 查找数组中最小元素 遍历 ArrayList 遍历 HashMap 遍历枚举 矩形面积 奇偶数判断 正负数判断 求平方根 随机数

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assert abstract boolean break byte case catch char class continue default do double else enum exports extends final finally float for if implements import instanceof int interface long module native new package private protected public return requires short static super switch synchronized this throw throws transient try var void volatile while
Java 字符串方法
charAt() codePointAt() codePointBefore() codePointCount() compareTo() compareToIgnoreCase() concat() contains() contentEquals() copyValueOf() endsWith() equals() equalsIgnoreCase() format() getBytes() getChars() hashCode() indexOf() isEmpty() join() lastIndexOf() length() matches() offsetByCodePoints() regionMatches() replace() replaceAll() replaceFirst() split() startsWith() subSequence() substring() toCharArray() toLowerCase() toString() toUpperCase() trim() valueOf()
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abs() acos() addExact() asin() atan() atan2() cbrt() ceil() copySign() cos() cosh() decrementExact() exp() expm1() floor() floorDiv() floorMod() getExponent() hypot() IEEEremainder() incrementExact() log() log10() log1p() max() min() multiplyExact() negateExact() nextAafter() nextDown() nextUp() pow() random() rint() round() scalb() signum() sin() sinh() sqrt() subtractExact() tan() tanh() toDegrees() toIntExact() toRadians() ulp()
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print() printf() println()
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compare() equals() sort() fill() length
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add() addAll() clear() clone() contains ensureCapacity() forEach() get() indexOf() isEmpty() iterator() lastIndexOf() listIterator() remove() removeAll() removeIf() replaceAll() retainAll() set() size() sort() spliterator() subList() toArray() trimToSize()
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clear() clone() compute() computeIfAbsent() computeIfPresent() containsKey() containsValue() entrySet() forEach() get() getOrDefault() isEmpty() keySet() merge() put() putAll() putIfAbsent() remove() replace() replaceAll() size() values()
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Java double 关键字

❮ Java 关键字

示例

double myNum = 19.99d;
System.out.println(myNum);

自己尝试 »

定义和用法

The double 关键字是一种数据类型，可以存储从 1.7e−308 到 1.7e+308 的小数。

注意，你应该用 "d" 结束值。

相关页面

阅读更多关于数据类型的信息，请访问我们的 Java 数据类型教程.

❮ Java 关键字

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