NSArray *array1 = [NSArray arrayWithObjects:@"todd1", @"todd2", @"todd3", nil];
bool objectMembership = [array1 containsObject:@"todd1"];
NSLog(@"%d",objectMembership);  // prints 1 or 0

注意，在Swift中，你可以这样做

let testBool: Bool = true
NSLog("testBool = %@", testBool.description)

这将记录testBool = true

我是这样做的:

BOOL flag = YES;
NSLog(flag ? @"Yes" : @"No");

?:是三元条件运算符，形式为:

condition ? result_if_true : result_if_false

在适当的地方替换实际的日志字符串。

你可以这样做:

BOOL flag = NO;
NSLog(flag ? @"YES" : @"NO");

//assuming b is BOOL. ternary operator helps us in any language.
NSLog(@"result is :%@",((b==YES)?@"YES":@"NO"));

%d, 0为假，1为真。

BOOL b; 
NSLog(@"Bool value: %d",b);

or

NSLog(@"bool %s", b ? "true" : "false");

基于数据类型%@的变化如下

For Strings you use %@
For int  you use %i
For float and double you use %f