比较字符时，ischar（x）&& x =='b'相当于strcmp（x，'b'）？(When comparing characters, is ischar(x) && x == 'b' equivalent to strcmp(x, 'b')?)

 在MATLAB中，我经常使用它来检查变量是否包含某个单个字符： 
 
if ischar(x) && x == 'b'
 
 为了减少混乱，我正在考虑将其改为： 
 
if strcmp(x, 'b')
 
 因为如果x不是字符或不等于'b' ，则比较将返回false，如您所料。 这些陈述在这种情况下是等同的还是有问题？ 
 
 更多信息： x == 'b'是不够的，因为当x == 98时返回true，但在某些情况下（如验证用户输入）， 98可能是无效输入而b 是有效输入。 此外，如果x不是标准数据类型（例如，如果它是对象），则第一个失败。 拿这个（愚蠢的）例子： 
 
x = table();
x == 'b'
 
 这会引发错误，因为没有为表定义eq ，但是strcmp(x, 'b')返回0，因为看起来strcmp也执行类型检查。 是否需要这种异常处理可能取决于具体情况。 

In MATLAB, I often use this to check if a variable contains a certain single character:
 
if ischar(x) && x == 'b'
 
to reduce clutter I'm thinking of changing it to this:
 
if strcmp(x, 'b')
 
because if x isn't a character or isn't equivalent to 'b', the comparison returns false as you would expect. Are these statements equivalent in this case or are there gotchas?
 
More info: x == 'b' isn't enough because this returns true when x == 98, but in certain cases (like validating user input), 98 may be invalid input while b is valid input. Also, the first one fails if x isn't a standard data type (if it's an object for example). Take this (stupid) example:
 
x = table();
x == 'b'
 
This throws an error because eq isn't defined for tables, but strcmp(x, 'b') returns 0 because it appears that strcmp also performs a type check. Whether or not this exception handling is desirable probably depends on the circumstances though.

原文：https://stackoverflow.com/questions/20848814