R中AND和OR逻辑运算符的短形式(&，|)和长形式(&&amp ;, ||)之间有什么区别? [英] What is the difference between short (&,|) and long (&&, ||) forms of AND, OR logical operators in R?

问题描述

可能重复:
R:链接条件应为&不是&&

Possible Duplicate:
R: subset() logical-and operator for chaining conditions should be & not &&

R中AND或OR逻辑运算符的短(&，|)和长(&&，||)形式之间有什么区别?

What is the difference between short (&,|) and long (&&, ||) forms of AND, OR logical operators in R?

例如:

1. x==0 & y==1
2. x==0 && y==1
3. x==0 | y==1
4. x==0 || y==1

1. x==0 & y==1
2. x==0 && y==1
3. x==0 | y==1
4. x==0 || y==1

我总是在代码中使用缩写形式.有障碍吗?

I always use the short forms in my code. Does it have any handicaps?

推荐答案

&和|-是元素方式的，可以与矢量运算配合使用，而||和&&始终生成单个TRUE或FALSE

& and | - are element-wise and can be used with vector operations, whereas, || and && always generate single TRUE or FALSE

区别:

> x <- 1:5
> y <- 5:1
> (x > 2) & (y < 3) 
  [1] FALSE FALSE FALSE  TRUE  TRUE
> (x > 2) && (y < 3) # here operaand && takes only 1'st elements from logical
                     # vectors (x>2) and (y<3)
> FALSE

因此，&&和||通常在if (condition) state_1 else state_2语句中使用，如下 处理长度为1

So, && and || are commonly used in if (condition) state_1 else state_2 statements, as dealing with vectors of length 1

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