This will allow you to use indexOf when there is still no native support. However, if you are more interested in all the little technical bits defined by the ECMA standard, and are less concerned about performance or conciseness, then you may find this more descriptive polyfill to be more useful. The following example uses indexOf to locate values in an array. Other parts are merely cosmetic conciseness. Fast-path it.
Let len be ToUint32 lenValue. If len is 0, return Let Pk be ToString k. If same is true, return k. A polyfill of Array. Reports the zero-based index of the first occurrence of the specified string in the current String object. Parameters specify the starting search position in the current string, the number of characters in the current string to search, and the type of search to use for the specified string.
Parameters specify the starting search position in the current string and the type of search to use for the specified string. Reports the zero-based index of the first occurrence of the specified character in this instance. The search starts at a specified character position and examines a specified number of character positions.
A parameter specifies the type of search to use for the specified string. Reports the zero-based index of the first occurrence of the specified string in this instance. Reports the zero-based index of the first occurrence of the specified Unicode character in this string. A parameter specifies the type of search to use for the specified character. The search starts at a specified character position. The zero-based index position of the value parameter from the start of the current instance if that string is found, or -1 if it is not.
If value is Empty , the return value is startIndex. The following example demonstrates three overloads of the IndexOf method that find the first occurrence of a string within another string using different values of the StringComparison enumeration. Index numbering starts from 0 zero. The startIndex parameter can range from 0 to the length of the string instance. The comparisonType parameter specifies to search for the value parameter using the current or invariant culture, using a case-sensitive or case-insensitive search, and using word or ordinal comparison rules.
Character sets include ignorable characters, which are characters that are not considered when performing a linguistic or culture-sensitive comparison.
In a culture-sensitive search that is, if comparisonType is not Ordinal or OrdinalIgnoreCase , if value contains an ignorable character, the result is equivalent to searching with that character removed.
If value consists only of one or more ignorable characters, the IndexOf String, Int32, Int32, StringComparison method always returns startIndex , which is the character position at which the search begins. Only one of the strings contains the required substring. If the example is run on the.
NET Framework 4 or later, in both cases, because the soft hyphen is an ignorable character, the method returns the index of "m" in the string when it performs a culture-sensitive comparison. When it performs an ordinal comparison, however, it finds the substring only in the first string.
Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m" when it performs a culture-sensitive comparison. The method returns the index of the soft hyphen in the first string only when it performs an ordinal comparison. Index numbering starts from 0. If startIndex equals the length of the string instance, the method returns If value consists only of one or more ignorable characters, the IndexOf String, Int32, StringComparison method always returns startIndex , which is the character position at which the search begins.
Note that in the case of the first string, which includes the soft hyphen followed by an "m", the method fails to return the index of the soft hyphen but instead returns the index of the "m". The zero-based index position of value from the start of the string if that character is found, or -1 if it is not. The following example demonstrates the IndexOf method. This method performs an ordinal culture-insensitive search, where a character is considered equivalent to another character only if their Unicode scalar values are the same.
To perform a culture-sensitive search, use the CompareInfo. The index position of the value parameter if that string is found, or -1 if it is not. If value is Empty , the return value is 0. If value consists only of one or more ignorable characters, the IndexOf String, StringComparison method always returns 0 zero to indicate that the match is found at the beginning of the current instance. Only one of the strings contains a soft hyphen. NET Framework 4 or later, because the soft hyphen is an ignorable character, a culture-sensitive search returns the same value that it would return if the soft hyphen were not included in the search string.
An ordinal search, however, successfully finds the soft hyphen in one string and reports that it is absent from the second string. The zero-based index position of value from the start of the current instance if that string is found, or -1 if it is not. The following example finds the index of all occurrences of the string "he" within a substring of another string. Note that the number of characters to be searched must be recalculated for each search iteration. This method performs a word case-sensitive and culture-sensitive search using the current culture.
In a culture-sensitive search, if value contains an ignorable character, the result is equivalent to searching with that character removed.
If value consists only of one or more ignorable characters, the IndexOf String, Int32, Int32 method always returns startIndex , which is the character position at which the search begins.
0コメント