iOS : how to replace occurrences of <null> in NSArray [duplicate] - ios

Question

This question already has answers here:
Replace all NSNull objects in an NSDictionary
(8 answers)
Closed 8 years ago.
I have an NSArray which contain string values, but sometimes it may contain null values also. I am getting that array like this,
(
"<null>",
"<null>",
"<null>",
"<null>",
"<null>"
)
I want to replace above by,
(
" ",
" ",
" ",
" ",
" "
)
That means I want to replace <null> by an empty string. how to achieve that ? I am aware of some string methods but that can not be implemented on array.

Answer 1

NSMutableArray *arr = [myNullArray mutableCopy];
for (int i=0; i < [arr count]; i++)
{
if ([[arr objectAtIndex:i] isKindOfClass:[NSNull Class]])
{
[arr inserObject:#" " atIndex:i];
}
}
NSLog(arr);

Answer 2

you would have to use the answer from here and iterate through each string in the array and perform the replacement of "<null>" with " "
edit: i think i misunderstood your question, if the array is containing NSNull objects, then you would still need to iterate through the array and just do a check like
for(int i = 0; i < array.count; i++){
if([array[i] isKindOfClass:[NSNull class]]){
array[i] = #" ";
}
}
disclaimer: havent tested code, just doing it off top of my head

Answer 3

You can try something like this.
for (NSInteger i = 0; i < array.count; i++) {
if ([array[i] isEqual:[NSNull null]] || [array[i] isEqual:#"<null>"]) {
[array replaceObjectAtIndex:i withObject:#" "];
}
}

Answer 4

First we need to understand, if it is a null string or the description taken from the log of an NSNull object. I suppose that array is your array. In the first case:
NSMutableArray * mutArr = #[].mutableCopy;
for (id obj in array) {
if ([obj isKindOfClass:NSString.class]) {
if ([obj isEqualToString:#"<null>"]) {
[mutArr addObject:#""];
}
else {
[mutArr addObject:obj];
}
else {
[mutArr addObject:obj];
}
}
array = mutArr.copy;
But I guess is the second:
NSMutableArray * mutArr = #[].mutableCopy;
for (id obj in array) {
if (obj == [NSNull null]) {
[mutArr addObject:#""];
}
else {
[mutArr addObject:obj];
}
}
array = mutArr.copy;
Just few hints that maybe can interest you:
If the original array is an NSArray is immutable and you can't change its content
during iteration don't remove/add object from the same array you are using for iteration or it will raise an exception
Mosto of times is the description of an NSNull object. NSNull is sneaky, because it can handle just few method and it's always source of crashes due to doesn't recognizeSelector
Fast enumeration is faster than common C for loop
swapping and substituting object in an array requires times

Answer 5

If you are using swift this would one way.
var stringArray = [String?]()
// Fill array with you stuff
// ...
// Check null (nil)
for string in stringArray
{
if string == nil
{
string = " "
}
}

Answer 6

NSMutableArray *anArray = [NSMutableArray arrayWithArray:yourArray];
for (id anObject in anArray) {
if((anObject) && (anObject != nil) && !([anObject
isKindOfClass:[NSNull class]]))
{
// if object is not nil
}
else{
anObject = #"";
}
}
yourArray = (NSArray *)anArray;