これにより、文字列の両端から空白が削除されます。
NSString *newString = [oldString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
文字列の右端から空白を削除するにはどうすればよいですか?
@ Regexidentと@Maxの回答に基づいて、次の方法を考え出しました。
@implementation NSString (SSToolkitAdditions)
#pragma mark Trimming Methods
- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
NSRange rangeOfFirstWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]];
if (rangeOfFirstWantedCharacter.location == NSNotFound) {
return @"";
}
return [self substringFromIndex:rangeOfFirstWantedCharacter.location];
}
- (NSString *)stringByTrimmingLeadingWhitespaceAndNewlineCharacters {
return [self stringByTrimmingLeadingCharactersInSet:
[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
NSRange rangeOfLastWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]
options:NSBackwardsSearch];
if (rangeOfLastWantedCharacter.location == NSNotFound) {
return @"";
}
return [self substringToIndex:rangeOfLastWantedCharacter.location+1]; // non-inclusive
}
- (NSString *)stringByTrimmingTrailingWhitespaceAndNewlineCharacters {
return [self stringByTrimmingTrailingCharactersInSet:
[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
@end
そして、これがGHUnitテストです。もちろんすべて合格です。
@interface StringCategoryTest : GHTestCase
@end
@implementation StringCategoryTest
- (void)testStringByTrimmingLeadingCharactersInSet {
NSCharacterSet *letterCharSet = [NSCharacterSet letterCharacterSet];
GHAssertEqualObjects([@"Zip90210Zip" stringByTrimmingLeadingCharactersInSet:letterCharSet], @"90210Zip", nil);
}
- (void)testStringByTrimmingLeadingWhitespaceAndNewlineCharacters {
GHAssertEqualObjects([@"" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @"", nil);
GHAssertEqualObjects([@"\n \n " stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @"", nil);
GHAssertEqualObjects([@"\n hello \n" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @"hello \n", nil);
}
- (void)testStringByTrimmingTrailingCharactersInSet {
NSCharacterSet *letterCharSet = [NSCharacterSet letterCharacterSet];
GHAssertEqualObjects([@"Zip90210Zip" stringByTrimmingTrailingCharactersInSet:letterCharSet], @"Zip90210", nil);
}
- (void)testStringByTrimmingTrailingWhitespaceAndNewlineCharacters {
GHAssertEqualObjects([@"" stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @"", nil);
GHAssertEqualObjects([@"\n \n " stringByTrimmingLeadingWhitespaceAndNewlineCharacters], @"", nil);
GHAssertEqualObjects([@"\n hello \n" stringByTrimmingTrailingWhitespaceAndNewlineCharacters], @"\n hello", nil);
}
@end
これらのメソッドを追加して、GitHubプルリクエストを SSToolkit に送信しました。
UPDATE:簡単なベンチマークでは、 Max ' &mineに基づいて Matt自身の適応 であることが示されました。最高のパフォーマンスを発揮します。
@implementation NSString (TrimmingAdditions)
- (NSString *)stringByTrimmingLeadingCharactersInSet:(NSCharacterSet *)characterSet {
NSUInteger location = 0;
NSUInteger length = [self length];
unichar charBuffer[length];
[self getCharacters:charBuffer];
for (location; location < length; location++) {
if (![characterSet characterIsMember:charBuffer[location]]) {
break;
}
}
return [self substringWithRange:NSMakeRange(location, length - location)];
}
- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
NSUInteger location = 0;
NSUInteger length = [self length];
unichar charBuffer[length];
[self getCharacters:charBuffer];
for (length; length > 0; length--) {
if (![characterSet characterIsMember:charBuffer[length - 1]]) {
break;
}
}
return [self substringWithRange:NSMakeRange(location, length - location)];
}
@end
その後:
NSString *trimmedString = [yourString stringByTrimmingTrailingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];
または先頭の空白の場合:
NSString *trimmedString = [yourString stringByTrimmingLeadingCharactersInSet:[NSCharacterset whitespaceAndNewlineCharacterSet]];
これは抽象的な方法で実装されているため、可能なNSCharacterSet
、whitespaceAndNewlineCharacterSet
をその1つとして使用できます。
便宜上、次のラッパーメソッドを追加することをお勧めします。
- (NSString *)stringByTrimmingLeadingWhitespace {
return [self stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}
- (NSString *)stringByTrimmingTrailingWhitespace {
return [self stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
}
- (NSString *)stringByTrimmingLeadingWhitespaceAndNewline {
return [self stringByTrimmingLeadingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
- (NSString *)stringByTrimmingTrailingWhitespaceAndNewline {
return [self stringByTrimmingTrailingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
}
編集:パフォーマンスを向上させるために、charBufferを使用して初期バージョンに戻しました。
NSString* str = @"hdskfh dsakjfh akhf kasdhfk asdfkjash fkadshf1234 ";
NSRange rng = [str rangeOfCharacterFromSet: [NSCharacterSet characterSetWithCharactersInString: [str stringByReplacingOccurrencesOfString: @" " withString: @""]] options: NSBackwardsSearch];
str = [str substringToIndex: rng.location+1];
最後の非末尾文字がマルチバイトの場合を考慮して、わずかな変更が必要です。
- (NSString *)stringByTrimmingTrailingCharactersInSet:(NSCharacterSet *)characterSet {
NSRange rangeOfLastWantedCharacter = [self rangeOfCharacterFromSet:[characterSet invertedSet]
options:NSBackwardsSearch];
if (rangeOfLastWantedCharacter.location == NSNotFound) {
return @"";
}
return [self substringToIndex:rangeOfLastWantedCharacter.location + rangeOfLastWantedCharacter.length]; // non-inclusive
}