# “if” statement using “or” operator.

조회 수: 7,361(최근 30일)
Sarah 2012년 2월 2일
답변: Rehman Tabasum 2021년 4월 30일
Hello everyone,
I have a very simple question....and I have been working on it for some time but cannot figure it out. This is essentially what I would LIKE to say:
for r = 1:length(FreqSec)-1
if FreqSec(1,r+1) > FreqSec(r)*1.01 "OR" FreqSec(1,r+1) <FreqSec(r)*0.99
LagStart = [FreqSec(1,r) r];
break;
end
end
FreqSec is a vector with lots and lots of values....generally within the range of 0.99 and 1.01, except for in a certain interval. I want to detect the exact index point at which the values start changing from the 0.99 to 1.01 range.
Thanks for the help in advance :)
##### 댓글 수: 1표시숨기기 없음
Aaron Eldridge 2016년 4월 28일
The "||" counts as an or on matlab

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### 채택된 답변

Walter Roberson 2012년 2월 3일
if FreqSec(1,r+1) > FreqSec(r)*1.01 | FreqSec(1,r+1) <FreqSec(r)*0.99
or
if FreqSec(1,r+1) > FreqSec(r)*1.01 || FreqSec(1,r+1) <FreqSec(r)*0.99
The first of these is more general. The second of these, , is the short-circuiting OR that does not bother to evaluate the second expression if it already knows the final result after the first operation. The operator can only be used between expressions that produce scalar outputs.
##### 댓글 수: 1표시숨기기 없음
Harry MacDowel 2013년 11월 23일
good clarification on the difference between | and !

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### 추가 답변(2개)

Geoff 2012년 2월 3일
So you want the last index within the valid range?
I don't know why you are multiplying by 1.01 and 0.99. Perhaps you have described the problem incorrectly or that is the cause of your difficulties. What I think you are trying to do is this:
idx = find( FreqSec >= 0.99 & FreqSec <= 1.01, 1, 'last' )
LagStart = [FreqSec(1,idx) idx];
Or, since it's symmetric:
idx = find( abs(FreqSec-1) <= 0.01, 1, 'last' )
If instead you want the index of the first out-of-range value, use:
idx = find( abs(FreqSec-1) > 0.01, 1, 'first' )
The parameter 'first' is optional, but good for clarity.
-g-
##### 댓글 수: 1표시숨기기 없음
Geoff 2012년 2월 3일
Oops, those statements with 'last' are incorrect. You are probably better off doing the 'first' statement and subtracting 1.

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Rehman Tabasum 2021년 4월 30일
i=5
while i>=-1
pause(1)
fprintf('%d\n',i)
i=i-1
if i==0
break
end
end
this is my code for the start button gui for countdown timer so anyone know how to stop coutdown timer when it is runnnig

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