黑马程序员--Foundation框架-NSS 4000 tring基本用法
2015-07-16 10:37
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------- android培训、java培训、期待与您交流!
----------
NSString基本方法
NSString *str = @”abc”;//str保存的是字符串常量,记得带*
NSString *str2 = [NSString new];
Str = @“abc”;//创建与赋值
格式化字符串:
NSString * str1 = @”Hello World”;
NSString * strn = [NSString stringWithFormat:@”%@ Hello Program”,str1];
NSString * strm =[[NSString alloc] initWithFormat:@”welcom to %@”,str1];
isEqualToString
NSString * s1 = @”This is a String”;
NSString * s2 = @”This is a String”;
BOOL ret = [a1 isEqualToString :s2];
NSLog (@”ret:%d”,ret);//YES
isEqualToString ,isEqual, == 区别
1.很重要的一点,OC对象都是用指针表示的, == 比较的是指针指向的地址
2.isEqual 是NSObject的方法,其先判断指针是否相等,相等直接YES,然后判断是否 同类,或者是否为空,非同类或者为空直接返回NO,接着对比其里面的属性是否相
等,如果都相等,则返回YES
3.isEqualToString 是isEqual的衍生,判断字符串是否相等
compare方法
NSString * s1 = @”Hello World”;
NSString * s2 = @”Hello World”;
BOOL ret = [s1 compare:s2] == NSOrderedSame;// YES
NSString * s3 = @”ABC Hello”;
BOOL ret2 = [s1 compare :s3] == NSOrderedAscending;//NO
BOOL ret3 = [s1 compare :s3] == NSOrderedDescending;//YES
//比较
BOOL ret4 = [s1 compare: s3 options:NSCaseInsensitiveSearch | NSNumbericSearch] == NSOrderedSame;
//NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较,区分大小写 NSNumericSearch:比较字符串的字符个数,而不是字符值。
大小写输出
NSString * s1 = @”string one”;
NSString * s2 = @”STRING TWO”;
NSString * s3 = @”hello ONE”;
NSLog(@”s1 的大写:%@”,[s1 uppercaseString]);
NSLog(@”s2 的小写:%@”,[se lowercaseString]);
NSLog(@”s3 的首字母:%@”,[s3 capitalizedString]);
rangeOfString
NSString *s1 = @"This is a string";
NSString *s2 = @"string";
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int len = range.length;
NSString*astring=[[NSString alloc]initWithString:[NSString stringWithFormat:@"location:%i,len:%i",location,len];
NSLog(@"astring:%@",astring);
[astring release];
substringToIndex
NSString *s1 = @"This is a string";
NSString *s2 = [s1 substringToIndex:3];//s2:Thi
substringFromIndex
NSString *s1 = @”ABCDEFGHIGK”;
NSString *s2 = [s1 substringFromIndex:3];//DEFGHIGK
substringWithRange
NSString * s3 = [s1 substringWithRange:NSMakeRange(0,4)];//ABCD
stringWithCapacity://按照固定长度生成空字符串
NSMutableString * s;
s = [NSMutableString stringWithCapacity:40];
appendString,appendFormat
NSMutableString * s1 = [[NSMutableString alloc] initWithString:@”ABCDEFG”];
[s1 appendString:@”,HIJKLMN”];
[s1 appendFormat:[NSString stringWithFormat:@”,OPQRST”]];
------- android培训、java培训、期待与您交流!
----------
----------
NSString基本方法
NSString *str = @”abc”;//str保存的是字符串常量,记得带*
NSString *str2 = [NSString new];
Str = @“abc”;//创建与赋值
格式化字符串:
NSString * str1 = @”Hello World”;
NSString * strn = [NSString stringWithFormat:@”%@ Hello Program”,str1];
NSString * strm =[[NSString alloc] initWithFormat:@”welcom to %@”,str1];
isEqualToString
NSString * s1 = @”This is a String”;
NSString * s2 = @”This is a String”;
BOOL ret = [a1 isEqualToString :s2];
NSLog (@”ret:%d”,ret);//YES
isEqualToString ,isEqual, == 区别
1.很重要的一点,OC对象都是用指针表示的, == 比较的是指针指向的地址
2.isEqual 是NSObject的方法,其先判断指针是否相等,相等直接YES,然后判断是否 同类,或者是否为空,非同类或者为空直接返回NO,接着对比其里面的属性是否相
等,如果都相等,则返回YES
3.isEqualToString 是isEqual的衍生,判断字符串是否相等
compare方法
NSString * s1 = @”Hello World”;
NSString * s2 = @”Hello World”;
BOOL ret = [s1 compare:s2] == NSOrderedSame;// YES
NSString * s3 = @”ABC Hello”;
BOOL ret2 = [s1 compare :s3] == NSOrderedAscending;//NO
BOOL ret3 = [s1 compare :s3] == NSOrderedDescending;//YES
//比较
BOOL ret4 = [s1 compare: s3 options:NSCaseInsensitiveSearch | NSNumbericSearch] == NSOrderedSame;
//NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较,区分大小写 NSNumericSearch:比较字符串的字符个数,而不是字符值。
大小写输出
NSString * s1 = @”string one”;
NSString * s2 = @”STRING TWO”;
NSString * s3 = @”hello ONE”;
NSLog(@”s1 的大写:%@”,[s1 uppercaseString]);
NSLog(@”s2 的小写:%@”,[se lowercaseString]);
NSLog(@”s3 的首字母:%@”,[s3 capitalizedString]);
rangeOfString
NSString *s1 = @"This is a string";
NSString *s2 = @"string";
NSRange range = [string1 rangeOfString:string2];
int location = range.location;
int len = range.length;
NSString*astring=[[NSString alloc]initWithString:[NSString stringWithFormat:@"location:%i,len:%i",location,len];
NSLog(@"astring:%@",astring);
[astring release];
substringToIndex
NSString *s1 = @"This is a string";
NSString *s2 = [s1 substringToIndex:3];//s2:Thi
substringFromIndex
NSString *s1 = @”ABCDEFGHIGK”;
NSString *s2 = [s1 substringFromIndex:3];//DEFGHIGK
substringWithRange
NSString * s3 = [s1 substringWithRange:NSMakeRange(0,4)];//ABCD
stringWithCapacity://按照固定长度生成空字符串
NSMutableString * s;
s = [NSMutableString stringWithCapacity:40];
appendString,appendFormat
NSMutableString * s1 = [[NSMutableString alloc] initWithString:@”ABCDEFG”];
[s1 appendString:@”,HIJKLMN”];
[s1 appendFormat:[NSString stringWithFormat:@”,OPQRST”]];
------- android培训、java培训、期待与您交流!
----------
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