NSString to int issue - iphone

Question

When I want to convert NSString to int
I use:
[string intValue];
But how to determine if string is int value? for instance to avoid situations like this:
[#"hhhuuukkk" intValue];

Answer 1

int value;
NSString *s = #"huuuk";
if([[NSScanner scannerWithString:s] scanInt:&value]) {
//Is int value
}
else {
//Is not int value
}
Edit: added isAtEnd check according to Martin R's suggestion. This will make sure it is only digits in the whole string.
int value;
NSString *s = #"huuuk";
NSScanner *scanner = [NSScanner scannerWithString:s];
if([scanner scanInt:&value] && [scanner isAtEnd]) {
//Is int value
}
else {
//Is not int value
}

Answer 2

The C way: use strtol() and check errno:
errno = 0;
int n = strtol(str.UTF8String, NULL, 0);
if (errno != 0) {
perror("strtol");
// or handle error otherwise
}
The Cocoa way: use NSNumberFormatter:
NSNumberFormatter *fmt = [[NSNumberFormatter alloc] init];
[fmt setGeneratesDecimalNumbers:NO];
NSNumber *num = nil;
NSError *err = nil;
NSRange r = NSMakeRange(0, str.length);
[fmt getObjectValue:&num forString:str range:&r error:&err];
if (err != nil) {
// handle error
} else {
int n = [num intValue];
}

Answer 3

NSString *yourStr = #"hhhuuukkk";
NSString *regx = #"(-){0,1}(([0-9]+)(.)){0,1}([0-9]+)";
NSPredicate *chekNumeric = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", regx];
BOOL isNumber = [chekNumeric evaluateWithObject:yourStr];
if(isNumber)
{
// Your String has only numeric value convert it to intger;
}
else
{
// Your String has NOT only numeric value also others;
}
For only integer value change Rgex pattern to ^(0|[1-9][0-9]*)$ ;

Answer 4

NSNumberFormatter * f = [[NSNumberFormatter alloc] init];
[f setNumberStyle:NSNumberFormatterDecimalStyle];
NSNumber * amt = [f numberFromString:#"STRING"];
if(amt)
{
// convert to int if you want to like you have done in your que.
//valid amount
}
else
{
// not valid
}

Answer 5

NSString *stringValue = #"hhhuuukkk";
if ([[NSScanner scannerWithString:stringValue] scanInt:nil]) {
//Is int value
}
else{
//Is not int value
}
[[NSScanner scannerWithString:stringValue] scanInt:nil] will check if "stringValue" has an integer value.
It returns a BOOL indicating whether or not it found a suitable int value.