从Python角度学Java基础

1. 变量

赋值数据类型 2. 符号

计算运算符比较运算符代码符注释文本符 3. if

一行if一次判断多次判断 4. for5. while6. 数组7. 程序结构8. 输入输出

输出输入 9. 异常捕获

// Java
x = a > b ? c : d;

# Python
x = c if a > b else d

// Javascript
x = a > b ? c : d

' VBA
if a > b Then x = c Else x = d

// Java
if (a > b) {
	x = c;
} else {
	x = d;
}

# Python
if a > b:
	x = c
else:
	x = d

// Javascript
if (a > b) {
	x = c
} else {
	x = d
}

' VBA
If a > b Then
	x = c
Else
	x = d
End If

// Java
if (a > b) {
	x = c;
} else if (a > bb) {
	x = cc;
} else {
	x = d;
}

# Python
if a > b:
	x = c
elif a > bb:
	x = cc
else:
	x = d

// Javascript
if (a > b) {
	x = c
} else if (a > bb) {
	x = cc
} else {
	x = d
}

' VBA
If a > b Then
	x = c
ElseIf a > bb Then
	x = cc
Else
	x = d
End If

下标循环

// Java
for (int i=0;i<100;i++) {	
	System.out.println(i);
}

# Python
for i in range(100):
	print(i)

// Javascript
for (var i=0;i<100;i++) {	
	console.log(i)
}

' VBA
For i = 1 to 100 step 1
	Debug.Print i
next

数组遍历循环

// Java
for (int a:arr) {
	System.out.print(a);
}

# Python
for a in arr:
	print(a)

// Javascript
for (a in arr) {
	console.log(a)
}

' VBA 
For Each a in arr
	Debug.Print a
Next

// Java
int i;
while (i < 100) {
	System.out.println(i);
	i++;
}

// java的另一个while
int i;
do {
	System.out.println(i);
	i++;
} while (i < 99);

# Python
i = 0
while True:
	if i < 100:
		print(i)
	else:
		break

// Javascript
i = 0
while (i < 100) {
	console.log(i)
	i++
}

' VBA
' 1
i = 0;
While i < 100
	Debug.Print(i)
Wend

' VBA
' 2
i = 0;
Do While i < 100
	Debug.Print(i)
Loop

' VBA
' 3
i = 0;
Do 
	Debug.Print(i)
Loop While i < 99

' VBA
' 4
i = 0;
Do Until i >= 100
	Debug.Print(i)
Loop

' VBA
' 5
i = 0;
Do
	Debug.Print(i)
Loop Until i >= 99

Java

public class Hello {
	public static void main(String[] args) {
		// 主程序说明
		userFunction usf = new userFunction();
		usf.setArg("Hello"); 
		System.out.println(usf.getArg());
		
	}
}	

class userFunction {
	private String arg;
	
	public void setArg(String arg) {
		// 设置
		this.arg = arg;
	}
	
	public String getArg() {
		// 返回
		return this.arg;
	}	
}

Python

'''
文档说明
'''

class userFunction:
	def __init__(self):
		pass
		
	def setArg(self,arg):
		self.arg = arg
	
	def getArg(self):
		return self.arg

if __name__ == '__main__':
	usf = userFunction()
	usf.setArg("Hello")
	print(usf.getArg())

Javascript

function userFunction(args) {
	x = process(args)
	return x
}

VBA

Sub userSub()
	x = userFunction(args)
	Debug.Print x
End Sub

Function userFunction(args) as String
	userFunction = process(args)
End Function

根据以往的代码来学新个人觉得会更高效一点
初学Java也有很多不懂,如有错误,请不吝指正