This question already has answers here:
How to convert string to integer in C#
(12 answers)
Closed 8 years ago.
I need to convert a string to integer. My string can be of any type (float/int/string/special character).
For example:
If my string is "2.3", I need to convert to = 2
If my string is "anyCharacter", I need to convert to = 0
If my string is "2", I need to convert to = 2
I tried the following:
string a = "1.25";int b = Convert.ToInt32(a);
I got the error:
Input string was not in a correct format
How do I convert it?
Use Double.TryParse() and once you get the value from it, convert it to int using Convert.ToInt():
double parsedNum;
if (Double.TryParse(YourString, out parsedNum) {
newInt = Convert.ToInt32(num);
}
else {
newInt = 0;
}
Try to parse it as a floating point number, and convert to integer after that:
double num;
if (Double.TryParse(a, out num) {
b = (int)num;
} else {
b = 0;
}
This should help: treat any string as if it were a double, then Math.Floor() it to round it down to the nearest integer.
double theNum = 0;
string theString = "whatever"; // "2.3"; // "2";
if(double.TryParse(theString, out theNum) == false) theNum = 0;
//finally, cut the decimal part
int finalNum = (int)Math.Floor(theNum);
NOTE: the if might not be needed per-se, due to theNum initialization, but it's more readable this way.
I think Convert.ToInt32 is the wrong place to look for - I would use Integer.Tryparse and if TryParse evaluates to false, assign a 0 to the variable. Before the TryParse, you could simply delete any character after the dot, if you find it in the string.
Also, keep in mind that some languages use "," as a separator.
Try:
if (int.TryParse(string, out int)) {
variable = int.Parse(string);
}
As far as I know, there isn't any generic conversion, so you'd have to do a switch to find out the type of the variable and then use either of the following (for each type):
int.Parse(string)
or
int.TryParse(string, out int)
The second one will return a boolean which you can use to see if the conversion passed or failed.
Your best option would be to use double or decimal parsing as this won't remove any decimal places, unlike int.
bool Int32.TryParse(string, out int)
The boolean return value indicates if the conversion was successful or not.
Try something like this:
public int ForceToInt(string input)
{
int value; //Default is zero
int.TryParse(str, out value);
return value;
}
This will do the trick. However I don't recommend taking this approach. It is better to control your input whereever you get it.
Related
This question already has answers here:
Input string was not in a correct format
(9 answers)
Closed 3 years ago.
C# CODE
I have a problem with my "Check in" form.
I want to multiply the txtsubtotal and txtadvancepayment.
In textchange if I put number on the txtadvancepayment, the overallresult is correct. But if I clear the txtadvancepayment (Incase when the user puts a wrong value) it would be error. The error says "Input string was not in a correct format."
What should I do?
My Code downward
int overalltotal = 0;
int a = Convert.ToInt32(txtsubtotal.Text);
int b = Convert.ToInt32(txtadvancepayment.Text);
overalltotal = a - b;
txttotalbalance.Text = overalltotal.ToString();
An empty string cannot be parsed as an int. As others have mentioned, you can use int.TryParse which accepts a string as the first parameter and an out int as the second parameter, which holds the parsed value. You could do this:
int overallTotal = 0;
int a = 0;
int b = 0;
// TryParse returns a bool
// If either of these fails, the variable a or b will keep the default 0 value
int.TryParse(txtSubtotal.Text, out a);
int.TryParse(txtAdvancePayment.Text, out b);
// Sum a and b
overallTotal = a + b;
If you want to show an error to the user that one or both fields isn't a valid integer, you can assign a bool variable such as var aIsNumber = int.TryParse(...) and then check if aIsNumber or bIsNumber is false. If so, then a and/or b could not be parsed to an int.
You could use Int32.TryParse.
Int32.Parse attempts to convert the string representation of a number to its 32-bit signed integer equivalent and returns value indicates whether the operation succeeded. This would mean, in case your textbox is empty or contains a invalid numeric representation, and the method would return false since it would not be able to convert it to int32
For example
if(Int32.TryParse(txtsubtotal.Text,out var a)
&& Int32.TryParse(txtadvancepayment.Text,out var b))
{
// Code which requires a and b
}
I'm trying to convert the string "127.0" to an integer.
I tried this function:
int getInt(string numStr)
{
int result;
int.TryParse(numStr, out result);
return result;
}
But when I call it as int x = getInt("127.0"); then int.TryParse() sets result to 0.
When I rewrite the function like this:
int getInt(string numStr)
{
result=Convert.ToInt32(numStr);
return result;
}
the same getInt() call throws this exception:
Input string was not in a correct format.
The issue here is that "127.0" is not an integer, it's a floating point number. You will need to parse it using one of the other floating point types (i.e. double, float, Decimal, etc.).
You may want to consider either stripping off any values after the decimal point and attempting to parse it, or parsing it as another type and casting it as an integer :
int result = (int)Convert.ToDouble("1.270");
You could also take advantage of the Math.Truncate() function which would give you the integer portion of your value :
int result = (int)Math.Truncate(Convert.ToDouble("127.0"));
First off, you need to check the return value of int.TryParse(). If it returns false, then the string could not be converted.
Had you done that, you would see it returned false because 127.0 does not describe an integer value (it describes a floating point value).
Note that decimal.TryParse() would succeed here. You need to figure out if you need an integer or floating point value, and reject data that is incorrect.
An int cannot contain a decimal point; that makes it either a double, a float, or a decimal. Try to pull the number minus anything from the decimal point over to the right, like this:
int getInt(string numStr)
{
int result;
string[] splitup;
string number;
if (numstr.Contains('.'))
{
splitup = numstr.Split('.');
number = splitup[0];
int.TryParse(number, out result);
}
else
{
int.TryParse(numstr, out result);
}
return result;
}
Rion Williams is absolutely correct, IMHO.
Along with the fact that what you are parsing is not an integer, I'd personally use the TryParse method. Many of the .NET types have it, and it's quite a bit "safer" (it won't throw exceptions) than just parsing a string.
Example:
string stringValue = "127.0";
int intValue;
if(Int32.TryParse(stringValue, out intValue))
{
// return value
}
// handle the failure
If you don't like that, I'd wrap it in a try-catch...
My code is like this
string asd = "24000.0000";
int num2;
if (int.TryParse(asd, out num2))
{
// It was assigned.
}
Now code execution never enters to if case, that means try parse is not working. Can any one tell me whats wrong with the code.
Note:In first step The value 24000.0000 is purposefully assigned as string .
Use the second TryParse overload that allows you to specify NumberStyle parameters to allow for decimals.
int val =0;
var parsed = int.TryParse("24000.0000",
NumberStyles.Number,
CultureInfo.CurrentCulture.NumberFormat,
out val);
For an int, you cannot have decimal places.
EDIT:
string asd = "24000.000";
int dotPos = asd.LastIndexOf('.');
if (dotPos > -1) {
asd = asd.Substring(0, dotPos);
}
int num2;
if (int.TryParse(asd, out num2))
{
// It was assigned.
}
EDIT:
As pointed out by other answers, there are better ways to deal with the conversion.
See the remarks section of the MSDN documentation on this method:
http://msdn.microsoft.com/en-us/library/f02979c7.aspx
The string can only contain whitespace, a sign, and digits.
This should work for you:
string asd = "24000.0000";
int num2;
decimal tmpNum;
if (decimal.TryParse(asd, out tmpNum))
{
num2 = (int)tmpNum;
// It was assigned.
}
You've asked it to parse an int but given it a double or float. Since it can't parse the number it'll return false and set num2 to zero.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
C# int.parse issue with leading zeros
How can i correct this as a int with leading Zeroes.Actually need to ignore/remove FormatException.
string value = "055";
int x = int.Parse(value);
It works fine on my system.
Probably the problem is with the current culture, you may try
string value = "055";
int x = int.Parse(value, CultureInfo.InvariantCulture);
Try this:
string value = "055";
int x;
if (int.TryParse(value, NumberStyles.Number, CultureInfo.InvariantCulture,out x ))
{
//use x
}
//use x ; x will be zero if it fails parsing.
Use Int32.TryParse
string value = "055";
int x = 0;
if(int.TryParse(value, out x))
{
//use x
}
I have tested and x gets 55 and it goes inside if statement.
Try out this..
int x = int.parse(value.TrimStart('0'));
Leading zeros is C variant actually means that a number should be interpreted as octal, I'm suprised .net throws an exception>
In any event
value.TrimStart('0');
you should try to use TryParse if you are not sure if it could be parsed
else try
int.Parse(value,CultureInfo.InvariantCulture);
If leading zeros is actually a problem (check if you can do int.Parse("0") ) then it might be a different issue which is explained here : localization components of Windows (not .NET)
I have a Double which could have a value from around 0.000001 to 1,000,000,000.000
I wish to format this number as a string but conditionally depending on its size. So if it's very small I want to format it with something like:
String.Format("{0:.000000000}", number);
if it's not that small, say 0.001 then I want to use something like
String.Format("{0:.00000}", number);
and if it's over, say 1,000 then format it as:
String.Format("{0:.0}", number);
Is there a clever way to construct this format string based on the size of the value I'm going to format?
Use Math.Log10 of the absolute value of the double to figure out how many 0's you need either left (if positive) or right (if negative) of the decimal place. Choose the format string based on this value. You'll need handle zero values separately.
string s;
double epislon = 0.0000001; // or however near zero you want to consider as zero
if (Math.Abs(value) < epislon) {
int digits = Math.Log10( Math.Abs( value ));
// if (digits >= 0) ++digits; // if you care about the exact number
if (digits < -5) {
s = string.Format( "{0:0.000000000}", value );
}
else if (digits < 0) {
s = string.Format( "{0:0.00000})", value );
}
else {
s = string.Format( "{0:#,###,###,##0.000}", value );
}
}
else {
s = "0";
}
Or construct it dynamically based on the number of digits.
Use the # character for optional positions in the string:
string.Format("{0:#,###,##0.000}", number);
I don't think you can control the number of decimal places like that as the precision of the double will likely mess things up.
To encapsulate the logic of deciding how many decimal places to output you could look at creating a custom formatter.
The first two String.Format in your question can be solved by automatically removing trailing zeros:
String.Format("{0:#,##0.########}", number);
And the last one you could solve by calling Math.Round(number,1) for values over 1000 and then use the same String.Format.
Something like:
String.Format("{0:#,##0.########}", number<1000 ? number : Math.Round(number,1));
Following up on OwenP's (and by "extension" tvanfosson):
If it's common enough, and you're on C# 3.0, I'd turn it into an extension method on the double:
class MyExtensions
{
public static string ToFormmatedString(this double d)
{
// Take d and implement tvanfosson's code
}
}
Now anywhere you have a double you can do:
double d = 1.005343;
string d_formatted = d.ToFormattedString();
If it were me, I'd write a custom wrapper class and put tvanfosson's code into its ToString method. That way you could still work with the double value, but you'd get the right string representation in just about all cases. It'd look something like this:
class FormattedDouble
{
public double Value { get; set; }
protected overrides void ToString()
{
// tvanfosson's code to produce the right string
}
}
Maybe it might be better to make it a struct, but I doubt it would make a big difference. You could use the class like this:
var myDouble = new FormattedDouble();
myDouble.Value = Math.Pi;
Console.WriteLine(myDouble);