正则表达式 – 如何编写C#正则表达式模式以匹配基本的printf格式

string input = "Bloke %s drank %5.2f litres of water and ate %d bananas";
string pattern = @"%(d+(.d+)?)?(d|f|s)";

foreach (Match m in Regex.Matches(input,pattern))
{
    Console.WriteLine(m.Value);
}

我没有在我的模式中使用[dfs],因为我计划更新它以使用命名组.这是基于your earlier question关于确定C风格格式字符串的替换策略.

这是一个想法：

string input = "Bloke %s drank %5.2f litres of water and ate %d bananas";
string pattern = @"%(?<Number>d+(.d+)?)?(?<Type>d|f|s)";

int count = 0;
string result = Regex.Replace(input,pattern,m =>
{
    var number = m.Groups["Number"].Value;
    var type = m.Groups["Type"].Value;
    // now you can have custom logic to check the type appropriately
    // check the types,format with the count for the current parameter
    return String.Concat("{",count++,"}");
});

C#/.NET 2.0方法：

private int formatCount { get; set; }

void Main()
{
    string input = "Bloke %s drank %5.2f litres of water and ate %d bananas";
    Console.WriteLine(FormatCStyleStrings(input));  
}

private string FormatCStyleStrings(string input)
{
    formatCount = 0; // reset count
    string pattern = @"%(?<Number>d+(.d+)?)?(?<Type>d|f|s)";
    string result = Regex.Replace(input,FormatReplacement);
    return result;
}

private string FormatReplacement(Match m)
{
    string number = m.Groups["Number"].Value;
    string type = m.Groups["Type"].Value;
    // custom logic here,format as needed
    return String.Concat("{",formatCount++,"}");
}