R if else语句中的奇怪行为

我刚开始做R编程。当我试图写我的第一个if-else语句时，我遇到了一个奇怪的行为，我不明白

当我运行以下代码时：

x = 4;
y=4;
        if (x==y) {
      print('they are equal');
    } else {
      print('they are not equal');
    }

我没有得到错误，我得到了预期的输出。但是，当我更改相同代码的缩进时，如下所示：

if(x==y){print('they are equal');}
else{print('they are not equal');}  

我收到一条错误消息，在“else”中显示“error:unexpected'else”

---

那么这是否意味着R像Python一样是一种缩进敏感语言？

根据我有限的经验，在Rsyntex中，

else

语句应该从

if

语句结束的同一行开始。否则，它将不起作用。而R对缩进不敏感。比如说,

这将起作用

if(x==y){print('they are equal')
  } else
    {print('they are not equal')}  



[1] "they are equal"

if(x==y){print('they are equal')} else
{print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} else {print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} 
else {
  print('they are not equal')}  

即使这样也会起作用

if(x==y){print('they are equal')
  } else
    {print('they are not equal')}  



[1] "they are equal"

if(x==y){print('they are equal')} else
{print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} else {print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} 
else {
  print('they are not equal')}  

这也会起作用

if(x==y){print('they are equal')
  } else
    {print('they are not equal')}  



[1] "they are equal"

if(x==y){print('they are equal')} else
{print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} else {print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} 
else {
  print('they are not equal')}  

但是您编写的代码不起作用，因为

else

语句不是从

if

语句结束的同一行开始的。另一个例子是

这行不通

if(x==y){print('they are equal')
  } else
    {print('they are not equal')}  



[1] "they are equal"

if(x==y){print('they are equal')} else
{print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} else {print('they are not equal')}  

[1] "they are equal"

if(x==y){print('they are equal')} 
else {
  print('they are not equal')}  

---

另外，您不需要分号。

来自文档：

请注意，忘记在语句周围加括号（{..}）是一个常见的错误，例如，在if（..）或for（..）之后。特别是，}和else之间不应该有换行符，以避免在输入if。。。else在键盘上或通过源代码进行构造请删除分号。R不是C，在R中，分号表示指令的结束，因此
print（'它们不相等'）
实际上是两条指令：
print（‘它们不相等’）；NULL
打印和
NULL
说明。@RuiBarradas:我同意，不需要分号。编辑了我的答案。