I have a string containing a pure number, but numberFromString returns nil.
Any idea why?
My code:
NSString *fText = #"33";
NSNumberFormatter *formatter;
NSNumber *fNum = [formatter numberFromString:fText];
NSLog(#"Number is %i", [fNum integerValue];
prints 0, and debugs as NIL.
Am I missing something in the formatter properties?
Thanks !
Your NSNumberFormatter is not initialized, so it is nil, and returning nil for the NSNumber.
Try:
NSNumberFormatter *formatter = [[NSNumberFormatter alloc]init];
NSNumber* fNum = [formatter numberFromString:fText];
It should work then.
I have a UITextField, which I am trying to use a NSNumberFormatter with a NSNumberFormatterDecimalStyle to convert the text field into an NSNumber to initialise an object.
However when I do this, I can't get any sensible results out of the conversion. For the purpose of this example I have replaced the UITextField with a string, but I still get strange results. I am sure I am doing something daft, but any help would be appreciated.
//NSString * boardNumberText = self.txtBoardNumbs.text;
NSString * boardNumberText = #"42";
NSNumberFormatter * formatter = [[NSNumberFormatter alloc] init];
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
NSNumber * boardNumber = [formatter numberFromString:boardNumberText];
if ([boardNumber isEqual:nil]) {
NSLog(#"Number was null");
}
NSLog(#"Number was not null");
[self.board setNumber:boardNumber];
NSLog(boardNumberText);
NSLog([NSString stringWithFormat:#"%d", boardNumber]);
NSLog([NSString stringWithFormat:#"%d", self.board.number]);
The output that I get from the log file when I run this is:
2012-07-15 16:54:26.564 CoreDataDev[16123:fb03] Number was not null
2012-07-15 16:54:26.564 CoreDataDev[16123:fb03] 42
2012-07-15 16:54:26.565 CoreDataDev[16123:fb03] 135821152
2012-07-15 16:54:26.565 CoreDataDev[16123:fb03] 135820272
You can't just log NSNumber to the console using the integer format specifier, since NSNumber is a wrapper object. Also, NSLog takes a format string, so you don't need to use stringWithFormat:. Try this instead:
NSLog(#"%d", [boardNumber intValue]);
Using
NSLog(#"%d", boardNumber);
is wrong: it prints the memory address of the boardNumber pointer (the NSNumber instance itself). Use
NSLog(#"%d", [boardNumber intValue]);
instead.
P. s.: that
NSLog([NSString stringWithFormat:...]);
is unnecessary and ugly; NSLog has built-in format string handling, use it!
NSString * addString=[arrayyyy componentsJoinedByString:#","];
NSLog(#"add string is: %#",addString);// result is: 45,1
Now I want to convert above string into integer.
I have tried this:
NSInteger myInt=[addString intValue];
//NSLog(#"myInt is: %d",myInt);// result is: 45
If you expected 45.1 then there are two things wrong :
45.1 is not an integer. You would have to use floatValue to read the value.
45,1 (notice the comma) is not a valid float number. While 45,1 is valid in some locale (i.e. in french its 1 000,25 instead of 1,000.25) you would have to convert the string with an NSNumberFormatter before reading the floatValue.
.
// Can't compile and verify this right now, so please bear with me.
NSString *str = #"45,1";
NSNumberFormatter *formatter = [[[NSNumberFormatter alloc] init] autorelease];
NSLocale *locale = [[[NSLocale alloc] initWithLocaleIdentifier:#"fr_FR"] autorelease]; // lets say French from France
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
[formatter setLocale:locale];
float value = [[formatter numberFromString:str] floatValue]; // value = 45.1
Try out NSExpression which works with mathematical symbols too (i.e. +, -, /, *):
NSNumber *numberValue = [[NSExpression expressionWithFormat:inputString] expressionValueWithObject:nil context:nil];
// do something with numberValue
From reading the question a lot, I think I may understand what you want.
The starting point seems to be:
NSLog(#"add string is: %#",addString);// result is: 45,1
And the current ending point is:
NSLog(#"myInt is: %d",myInt);// result is: 45
But it seems that you still want to print out 45,1
My guess on this is that you have an array of 2 strings [#"45",#"1"] called arrayyyy and you want to print out both values as integers. If this is so then what I think you want is:
NSInteger myInt1 = [[arrayyyy objectAtIndex:0] intValue];
NSInteger myInt2 = [[arrayyyy objectAtIndex:1] intValue];
NSLog(#"add string is: %d,%d",myInt1,myInt2);
Note This will crash horribly with an NSRangeException if there are not at least two strings in the array. So at the very least you should do:
NSInteger myInt1 = -1;
NSInteger myInt2 = -1;
if ([arrayyyy length] >0) myInt1 = [[arrayyyy objectAtIndex:0] intValue];
if ([arrayyyy length] >1) myInt2 = [[arrayyyy objectAtIndex:1] intValue];
NSLog(#"add string is: %d,%d",myInt1,myInt2);
But even this is bad as it assumes that the guard value of -1 will not be present in the actual data.
I copied this code from another post. I tried the example, however, I am getting a EXEC_BAD_ACCESS. From what I have read, this error happens when trying to use an object that has been deallocated, but I just don't see where I am doing that:
The call
...
float weighted_average = num_of_passes / total_of_all_passes;
NSString *newNumber = [[NSString alloc] init];
newNumber = [self formattedStringWithDecimal:weightedAverage]; //weighted average (float) = 15.875145
...
The Function
- (NSString *)formattedStringWithDecimal:(NSDecimalNumber *)decimalNumber
{
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
[formatter setMaximumFractionDigits:2]; //two deimal spaces
[formatter setRoundingMode: NSNumberFormatterRoundHalfUp]; //round up
NSString *result =[NSString stringWithString:[formatter stringFromNumber:decimalNumber]];
[formatter release];
return result;
}
Call the method like this:
newNumber = [self formattedStringWithDecimal:[NSDecimalNumber numberWithFloat:15.434]];
You've tried to pass a primitive, but the method expects an object: an NSDecimalNumber. You've got to use the static convenience method numberWithFloat to create an object of that type.
And by the way, I have the feeling that
newNumber = [NSString stringWithFormat#"%.2f", 15.434];
could achieve the same result with less lines of code. Note this will not round up your number though.
You are returning an autoreleased object. Does the function that uses it retain it? If not, it could be released and then later (later run loop) its trying to be (re)used. Agreed on the enabling zombies to spot that kind of thing.
How can I convert a NSString containing a number of any primitive data type (e.g. int, float, char, unsigned int, etc.)? The problem is, I don't know which number type the string will contain at runtime.
I have an idea how to do it, but I'm not sure if this works with any type, also unsigned and floating point values:
long long scannedNumber;
NSScanner *scanner = [NSScanner scannerWithString:aString];
[scanner scanLongLong:&scannedNumber];
NSNumber *number = [NSNumber numberWithLongLong: scannedNumber];
Thanks for the help.
Use an NSNumberFormatter:
NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterDecimalStyle;
NSNumber *myNumber = [f numberFromString:#"42"];
If the string is not a valid number, then myNumber will be nil. If it is a valid number, then you now have all of the NSNumber goodness to figure out what kind of number it actually is.
You can use -[NSString integerValue], -[NSString floatValue], etc. However, the correct (locale-sensitive, etc.) way to do this is to use -[NSNumberFormatter numberFromString:] which will give you an NSNumber converted from the appropriate locale and given the settings of the NSNumberFormatter (including whether it will allow floating point values).
Objective-C
(Note: this method doesn't play nice with difference locales, but is slightly faster than a NSNumberFormatter)
NSNumber *num1 = #([#"42" intValue]);
NSNumber *num2 = #([#"42.42" floatValue]);
Swift
Simple but dirty way
// Swift 1.2
if let intValue = "42".toInt() {
let number1 = NSNumber(integer:intValue)
}
// Swift 2.0
let number2 = Int("42')
// Swift 3.0
NSDecimalNumber(string: "42.42")
// Using NSNumber
let number3 = NSNumber(float:("42.42" as NSString).floatValue)
The extension-way
This is better, really, because it'll play nicely with locales and decimals.
extension String {
var numberValue:NSNumber? {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
return formatter.number(from: self)
}
}
Now you can simply do:
let someFloat = "42.42".numberValue
let someInt = "42".numberValue
For strings starting with integers, e.g., #"123", #"456 ft", #"7.89", etc., use -[NSString integerValue].
So, #([#"12.8 lbs" integerValue]) is like doing [NSNumber numberWithInteger:12].
You can also do this:
NSNumber *number = #([dictionary[#"id"] intValue]]);
Have fun!
If you know that you receive integers, you could use:
NSString* val = #"12";
[NSNumber numberWithInt:[val intValue]];
Here's a working sample of NSNumberFormatter reading localized number NSString (xCode 3.2.4, osX 10.6), to save others the hours I've just spent messing around. Beware: while it can handle trailing blanks ("8,765.4 " works), this cannot handle leading white space and this cannot handle stray text characters. (Bad input strings: " 8" and "8q" and "8 q".)
NSString *tempStr = #"8,765.4";
// localization allows other thousands separators, also.
NSNumberFormatter * myNumFormatter = [[NSNumberFormatter alloc] init];
[myNumFormatter setLocale:[NSLocale currentLocale]]; // happen by default?
[myNumFormatter setFormatterBehavior:NSNumberFormatterBehavior10_4];
// next line is very important!
[myNumFormatter setNumberStyle:NSNumberFormatterDecimalStyle]; // crucial
NSNumber *tempNum = [myNumFormatter numberFromString:tempStr];
NSLog(#"string '%#' gives NSNumber '%#' with intValue '%i'",
tempStr, tempNum, [tempNum intValue]);
[myNumFormatter release]; // good citizen
I wanted to convert a string to a double. This above answer didn't quite work for me. But this did: How to do string conversions in Objective-C?
All I pretty much did was:
double myDouble = [myString doubleValue];
Thanks All! I am combined feedback and finally manage to convert from text input ( string ) to Integer. Plus it could tell me whether the input is integer :)
NSNumberFormatter * f = [[NSNumberFormatter alloc] init];
[f setNumberStyle:NSNumberFormatterDecimalStyle];
NSNumber * myNumber = [f numberFromString:thresholdInput.text];
int minThreshold = [myNumber intValue];
NSLog(#"Setting for minThreshold %i", minThreshold);
if ((int)minThreshold < 1 )
{
NSLog(#"Not a number");
}
else
{
NSLog(#"Setting for integer minThreshold %i", minThreshold);
}
[f release];
I think NSDecimalNumber will do it:
Example:
NSNumber *theNumber = [NSDecimalNumber decimalNumberWithString:[stringVariable text]]];
NSDecimalNumber is a subclass of NSNumber, so implicit casting allowed.
What about C's standard atoi?
int num = atoi([scannedNumber cStringUsingEncoding:NSUTF8StringEncoding]);
Do you think there are any caveats?
You can just use [string intValue] or [string floatValue] or [string doubleValue] etc
You can also use NSNumberFormatter class:
you can also do like this code 8.3.3 ios 10.3 support
[NSNumber numberWithInt:[#"put your string here" intValue]]
NSDecimalNumber *myNumber = [NSDecimalNumber decimalNumberWithString:#"123.45"];
NSLog(#"My Number : %#",myNumber);
Try this
NSNumber *yourNumber = [NSNumber numberWithLongLong:[yourString longLongValue]];
Note - I have used longLongValue as per my requirement. You can also use integerValue, longValue, or any other format depending upon your requirement.
Worked in Swift 3
NSDecimalNumber(string: "Your string")
I know this is very late but below code is working for me.
Try this code
NSNumber *number = #([dictionary[#"keyValue"] intValue]]);
This may help you. Thanks
extension String {
var numberValue:NSNumber? {
let formatter = NumberFormatter()
formatter.numberStyle = .decimal
return formatter.number(from: self)
}
}
let someFloat = "12.34".numberValue