Binare optionen robot online seminar22 comments
Options made easy learn to trade stock options
You compare strings to answer one of two questions: The C examples in this article run in the Try. NET inline code runner and playground. Select the Run button to run an example in an interactive window.
Once you execute the code, you can modify it and run the modified code by selecting Run again. The modified code either runs in the interactive window or, if compilation fails, the interactive window displays all C compiler error messages.
When you compare strings, you define an order among them. Comparisons are used to sort a sequence of strings. Once the sequence is in a known order, it is easier to search, both for software and for humans. Other comparisons may check if strings are the same.
These sameness checks are similar to equality, but some differences, such as case differences, may be ignored. The most common operations, String. Equality use an ordinal comparison, a case-sensitive comparison, and use the current culture.
The results are shown in the following example. Ordinal comparisons do not take linguistic rules into account when comparing strings. They will compare the strings character by character. Case-sensitive comparisons use capitalization in their comparisons. The most important point about these default comparison methods is that because they use the current culture, the results depend on the locale and language settings of the machine where they run.
These comparisons are unsuitable for comparisons where order should be consistent across machines or locations. Equals method enables you to specify a StringComparison value of StringComparison. OrdinalIgnoreCase to specify a case-insensitive comparison. There is also a static Compare method that includes a boolean argument to specify case-insensitive comparisons. These are shown in the following code:. Strings can also be ordered using linguistic rules for the current culture.
This is sometimes referred to as "word sort order. For example, the hyphen "-" may have a very small weight assigned to it so that "co-op" and "coop" appear next to each other in sort order. In addition, some Unicode characters may be equivalent to a sequence of alphanumeric characterss.
The following example uses the phrase "They dance in the street. Linguistically in Windows , "ss" is equal to the German Essetz: This sample demonstrates the operating system dependent nature of linguistic comparisons. The host for the interactive window is a Linux host.
The linguistic and ordinal comparisons produce the same results. If you ran this same sample on a Windows host, you would see the following output:. On Windows, the sort order of "cop", "coop", and "co-op" change when you change from a linguistic comparison to an ordinal comparison.
The two German sentences also compare differently using the different comparison types. This sample stores CultureInfo for the current culture. The original culture can be set and retrieved on the current thread object.
The comparisons are performed using the CurrentCulture value to ensure a culture-specific comparison. The culture used affects linguistic comparisons. The following example shows the results of comparing the two German sentences using the "en-US" culture and the "de-DE" culture:. Culture-sensitive comparisons are typically used to compare and sort strings input by users with other strings input by users.
The characters and sorting conventions of these strings might vary depending on the locale of the user's computer. Even strings that contain identical characters might sort differently depending on the culture of the current thread. In addition, try this sample code locally on a Windows machine, and you will the following results:. Linguistic comparisions are dependent on the current culture, and are OS dependent. You must take that into account when you work with string comparisons.
The following examples show how to sort and search for strings in an array using a linguistic comparison dependent on the current culture. You use the static Array methods that take a System. Once the array is sorted, you can search for entries using a binary search.
A binary search starts in the middle of the collection to determine which half of the collection would contain the sought string. Each subsequent comparison subdivides the remaining part of the collection in half. The array is sorted using StringComparer. The local function ShowWhere displays information about where the string was found. If the string was not found, the returned value indicates where it would be if it were found. The following code uses the System.
This method needs a delegate that compares and orders two strings. CompareTo method provides that comparison function. Run the sample and observe the order. This sort operation uses an ordinal case sensitive sort. You would use the static String. Compare methods to specify different comparison rules. Once sorted, the list of strings can be searched using a binary search. The following sample shows how to search the sorted listed using the same comparison function. The local function ShowWhere shows where the sought text is or would be:.
Always make sure to use the same type of comparison for sorting and searching. Using different comparison types for sorting and searching produces unexpected results. Collection classes such as System. StringComparer parameter when the type of the elements or keys is string. In general, you should use these constructors whenever possible, and specify either StringComparer. None of the samples have used ReferenceEquals. This method determines if two strings are the same object.
This can lead to inconsistent results in string comparisons. The following example demonstrates the string interning feature of C. When a program declares two or more identical string variables, the compiler stores them all in the same location.
By calling the ReferenceEquals method, you can see that the two strings actually refer to the same object in memory. Copy method to avoid interning. After the copy has been made, the two strings have different storage locations, even though they have the same value.
Run the following sample to show that strings a and b are interned meaning they share the same storage. The strings a and c are not. When you test for equality of strings, you should use the methods that explicitly specify what kind of comparison you intend to perform.
Your code is much more maintainable and readable. Use the overloads of the methods of the System. Array classes that take a StringComparison enumeration parameter. You specify which type of comparison to perform. CompareTo instance methods always perform an ordinal case-sensitive comparison. They are primarily suited for ordering strings alphabetically. The feedback system for this content will be changing soon. Old comments will not be carried over.
If content within a comment thread is important to you, please save a copy. For more information on the upcoming change, we invite you to read our blog post. You can choose an ordinal or linguistic comparison. You can choose if case matters. You can choose culture specific comparisons. Linguistic comparisions are culture and platform dependent. Note The C examples in this article run in the Try.
Note When you test for equality of strings, you should use the methods that explicitly specify what kind of comparison you intend to perform.
Note The feedback system for this content will be changing soon.