google-diff- match-patch

Diff Match和Patch库提供强大的算法来执行同步纯文本所需的操作。 p>

Diff：

比较两个纯文本块，并有效地返回一个差异列表。

匹配：

给定一个搜索字符串，在一个纯文本块中找到***的模糊匹配。

修补程序：

将修补程序列表应用于纯文本。

目前提供Java，JavaScript，Dart，C ++，C＃，Objective C，Lua和蟒蛇。无论语言如何，每个库都具有相同的API和相同的功能。所有版本都有全面的测试工具。

有一个行或字差异 wiki页面，其中描述了如何进行逐行差异。

Hi I have two strings :

    String hear = "Hi My name is Deepak"
            + "\n"
            + "How are you ?"
            + "\n"
            + "\n"
            + "How is everyone";
    String dear = "Hi My name is Deepak"
            + "\n"
            + "How are you ?"
            + "\n"
            + "Hey there \n"
            + "How is everyone";

I want to get what is not present in the hear string that is "Hey There \n". I found a method , but it fails for this case :

static String strDiffChop(String s1, String s2) {
    if (s1.length() > s2.length()) {
        return s1.substring(s2.length() - 1);
    } else if (s2.length() > s1.length()) {
        return s2.substring(s1.length() - 1);
    } else {
        return "";
    }
}

Can any one help ?

google-diff-match-patch

The Diff Match and Patch libraries offer robust algorithms to perform the operations required for synchronizing plain text.

Diff:

Compare two blocks of plain text and efficiently return a list of differences.

Match:

Given a search string, find its best fuzzy match in a block of plain text. Weighted for both accuracy and location.

Patch:

Apply a list of patches onto plain text. Use best-effort to apply patch even when the underlying text doesn't match.

Currently available in Java, JavaScript, Dart, C++, C#, Objective C, Lua and Python. Regardless of language, each library features the same API and the same functionality. All versions also have comprehensive test harnesses.

There is a Line or word diffs wiki page which describes how to do line-by-line diffs.