How to use short if in flutter
this code can use:
1 + 1 == 2 ? print('check true') : print('check false');
Ans. print('check true')
but I want to do this:
1 + 1 == 2 ?? print('check true');
Why code can't print check true?
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1stackoverflow.com/questions/58910273/…Shubham Narkhede– Shubham Narkhede2021-01-12 13:07:16 +00:00Commented Jan 12, 2021 at 13:07
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The ?? is called null aware and checks if 1+1==2 is null. If the expression on the left of ?? evaluates to null then the print statement is executed.Calvin Gonsalves– Calvin Gonsalves2021-01-12 13:12:30 +00:00Commented Jan 12, 2021 at 13:12
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3 Answers
Simply
1 + 1 == 2 ? print('check true') : print('check false');
is equals to
if(1+1 == 2) {
print('check true');
else {
print('check false');
}
and
1 + 1 == 2 ?? print('check true');
is equals to
if((1+1 == 2) == null ) {
print('check true');
}
1 Comment
w461
just tried
1 + 1 == 2 ?? print('check true');. This does not work. ?? provides a default value in case the expression to the left is nullThe short form always require an else statement. And as said in the comments, ?? provides a default value if an object is null. With widgets, you could for example always write a == b ? c() : Container() because you cannot see Container() without a size
Comments
You can do this, I think is shorter and easy understand: if (1+1 == 2) print('check true');
