split string by indexOf

[N9]

Hi

Anyone who can help about split string.

string text = "History about a boy, who loves to play baseball with
his friends."

I like to find indexOf "play" and read the string 10 char left and 10
char right

The result: " loves to play baseball "

but my problem is, if I indexOf "his", it fail, because, " friends."
only had 9 char.

It's the same problem at the start of text.

anyone who can help ??

//N9

 

[Marc Gravell]

Smells like homework?

You need to adjust the ends if they go outside of the range...

int pre = 10, post = 10;
string text = "History about a boy, who loves to play baseball
with his friends.",
search = "play";
int index = text.IndexOf(search);
int start = index - pre, end = index + search.Length + post;
if (start < 0) start = 0;
if (end > text.Length) end = text.Length;
string subString = text.Substring(start, end - start);

Marc

 

[Jon Skeet [C# MVP]]

Smells like homework?

You need to adjust the ends if they go outside of the range...

int pre = 10, post = 10;
string text = "History about a boy, who loves to play baseball
with his friends.",
search = "play";
int index = text.IndexOf(search);
int start = index - pre, end = index + search.Length + post;
if (start < 0) start = 0;
if (end > text.Length) end = text.Length;
string subString = text.Substring(start, end - start);

An alternative to the last four lines:

int start = Math.Max(0, index-pre);
int end = Max.Min(text.Length, index+pre);
string subString = text.Substring(start, end-start);

Jon

 

[Jon Skeet [C# MVP]]

int end = Max.Min(text.Length, index+pre);

Sorry, this should be index+post, not index+pre.

Jon