正则表达式来修改字符串

Question

I have a string that I need to modify. The part that I need to modify is the end of the string. It is something like "to 23 May 2017". I just need to change the date that it is stored.

So I tried something like this:

var texto = System.Text.RegularExpressions.Regex.Replace(test, "to "+@"^\d{1,2}\/\?[A-z]?\/\d{4}","to { refundEnd: dd MMM yyyy}");

However, there is a problem with the regular expression because I am not matching the date. I am using the 'to' because there is another date in the string but this one does not need to be modified.

Any ideas?

Answer 1

Regex is only really useful in this instance if you actually want to do something with the date before you replace it (for example, the new date will be based on the current date). However, this doesn't seem to be the case based on your question.

If your date format is always going to be the same length, then you could always just trim off x characters from the end. But your current attempt suggests that the day part of the date will be unknown length (either one or two digits). Based on that I would suggest the best approach would be to use the position of "to" to identify what should be removed.

You could do this 2 different ways, take your pick:

---

The SPLIT method

Split the string on "to" and then rebuild the new string:

string[] values = test.Split("to");
string result = string.Format("{0} to {1}", values[0].Trim(), newDateString);

---

The SUBSTRING method

Create a substring based on the last index of "to" (we use last index in case there are any other matches earlier on in the string) which will provide you everything before "to" . Then you can append the rest on to the end:

string result = string.Format("{0} to {1}", test.Substring(0, test.LastIndexOf("to")).Trim(), newDateString);

Answer 2

In the end, what it worked for me was this:

var texto = System.Text.RegularExpressions.Regex
        .Replace(test, @"to\s+(\d{1,2})\s+([A-z]+)\s+(\d{4})", "to " 
         + refundEnd.ToString("dd MMM yyyy"));

It is a combination of two issues:

1.- getting the proper regular expression. 2.- formatting the new date.

Thanks everyone for the help!

Answer 3

干得好。

var texto = System.Text.RegularExpressions.Regex.Replace(test, @"to\s+(\d{1,2})\s+([A-z]+)\s+(\d{4})","to { refundEnd: $1 $2 $3}");

Answer 4

You can just remove the last 11 characters and concatenate the new date you want to suffix it with.

 //Your New Date string
 String yourDate = "dd MMM YYYY";
 var texto = test.Remove(test.Length - 11, 11)+yourDate;