I just want to know, whether a String variable contains a parsable positive integer value. I do NOT want to parse the value right now.
Currently I am doing:
int parsedId;
if (
(String.IsNullOrEmpty(myStringVariable) ||
(!uint.TryParse(myStringVariable, out parsedId))
)
{//..show error message}
This is ugly - How to be more concise?
Note: I know about extension methods, but I wonder if there is something built-in.
You could use char.IsDigit :
bool isIntString = "your string".All(char.IsDigit)
Will return true
if the string is a number
bool containsInt = "your string".Any(char.IsDigit)
Will return true
if the string contains a digit
假设您要检查字符串中的所有字符是否都是数字,您可以使用Enumerable.All 扩展方法和Char.IsDigit 方法,如下所示:
bool allCharactersInStringAreDigits = myStringVariable.All(char.IsDigit);
Maybe this can help
string input = "hello123world";
bool isDigitPresent = input.Any(c => char.IsDigit(c));
answer from msdn .
You can check if string contains numbers only:
Regex.IsMatch(myStringVariable, @"^-?\d+$")
But number can be bigger than Int32.MaxValue
or less than Int32.MinValue
- you should keep that in mind.
Another option - create extension method and move ugly code there:
public static bool IsInteger(this string s)
{
if (String.IsNullOrEmpty(s))
return false;
int i;
return Int32.TryParse(s, out i);
}
That will make your code more clean:
if (myStringVariable.IsInteger())
// ...
Sorry, didn't quite get your question. So something like this?
str.ToCharArray().Any(char.IsDigit);
Or does the value have to be an integer completely, without any additional strings?
if(str.ToCharArray().All(char.IsDigit(c));
这对我有用。
("your string goes here").All(char.IsDigit)
The answer seems to be just no.
Although there are many good other answers, they either just hide the uglyness (which I did not ask for) or introduce new problems (edge cases).
string text = Console.ReadLine();
bool isNumber = false;
for (int i = 0; i < text.Length; i++)
{
if (char.IsDigit(text[i]))
{
isNumber = true;
break;
}
}
if (isNumber)
{
Console.WriteLine("Text contains number.");
}
else
{
Console.WriteLine("Text doesn't contain number.");
}
Console.ReadKey();
Or Linq:
string text = Console.ReadLine();
bool isNumberOccurance =text.Any(letter => char.IsDigit(letter));
Console.WriteLine("{0}",isDigitPresent ? "Text contains number." : "Text doesn't contain number.");
Console.ReadKey();
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