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//字符串的创建与使用
#import<Foundation/Foundation.h>
int main(int argc, const char argv[])
{
@autoreleasepool{
//创建一个字符串常量
NSString *string1 = @"Hello";
//创建一个空的字符串
NSString *string2 = [[NSString alloc] init];
NSString *string3 = [NSString string];
//快速创建一个字符串(常量区）
NSString *string4 = [[NSString alloc] initWithString:@"Hello"];
NSString *string5 = [NSString stringWithString:@"Hello"];
NSString *string8 = [NSString stringWithString:@"Hello"];
//快速创建一个格式化字符串（堆区）
int number = 2;
NSString *string6 = [[NSString alloc] initWithFormat:@"%d", number];
NSString *string7 = [NSString stringWithFormat:@"浮点数：%f",10.8];
NSString *string9 = [NSString stringWithFormat:@"浮点数：%f",10.8];
//测试字符串内容是否相同
if([string6 isEqualToString:string7])
NSLog(@"Same content");
else
NSLog(@"Different content");
//输出：Different content
if([string4 isEqualToString:string5])
NSLog(@"Same content");
else
NSLog(@"Different content");
//输出：Same content
//测试两个字符串是否为同一对象
if(string5 == string8)
NSLog(@"Same point");
else
NSLog(@"Different point");
//输出：Same point
if(string7 == string9)
NSLog(@"Same point");
else
NSLog(@"Different point");
//输出：Different point
//比较字符串的大小
NSString *string10 = [[NSString alloc] initWithFormat:@"a"];
NSString *string11 = [[NSString alloc] initWithFormat:@"b"];
NSComparisonResult result = [string10 caseInsensitiveCompare:string11];
NSLog(@"%d", result);
//输出：-1 （升序）
//求字符串的长度
NSLog(@"%d", [string11 length]);
//输出：1
//字符串大小转换
NSString *string12 = @"Hello wORld";
NSLog(@"upper: %@", [string12 uppercaseString]); //全部转换成大写
NSLog(@"lower: %@", [string12 lowercaseString]); //全部转换成小写
NSLog(@"capital: %@", [string12 capitalizedString]); //首字母大写
//输出：HELLO WORLD
hello world
Hello World
//转换成基本数据类型。。。。。
NSString *string13 = @"3.14";
float pi = [string13 floatValue];
NSLog(@"pi : %.2f", pi);
//输出：3.14
//字符串转换成数组
NSString *string14 = @"abc xyz";
NSArray *array = [string14 componentsSeparatedByString:@" "); //以空格为间隔
NSLog(@"%@", array);
//输出：abc
xyz
//截取字符串
NSString *string15 = @"abcde";
NSString *subString1 = [string15 substringToIndex:2]; //截取到底2位
NSString *subString2 = [string15 substringFromIndex:2]; //从第2位开始截取
NSLog(@"%@", subString1);
NSLog(@"%@", subString2);
//输出：ab
cde
NSRange range; //NSRange range = {3, 2};
range.location = 3;
range.length = 2;
NSString *subString3 = [string15 substringWithRange:range];
NSLog(@"%@", subString3);
//输出：de
//字符串的拼接
NSString *string16 = @"abc";
NSString *string17 = @"xyz";
NSString *appString1 = [[NSString alloc] initWithFormat:@"%@%@", string16, stirng17];
NSString *appString2 = [string16 stringByAppendingFormat:@"%@", string17];
NSString *appString3 = [string16 stringByAppendingString:string17];
NSLog(@"%@, %@, %@", appString1, appString2, appString3);
//输出：abcxyz, abcxyz, abcxyz
//查找字符串
NSString *link = @"abcdeftarget=_blankxyz";
NSRange range1 = [link rangeOfString:@"target=_blank"];
NSLog(@"%@", NSStringFromRange(range1));
//输出：（6,13）
if(range1.location != NSNotFound)
NSLog(@"Founded");
//输出：Founded
/******************可变字符串操作*************************/
NSMutableString *mutableString1 = [[NSMutableString alloc] initWithFormat:@"abc"];
//插入
[mutableString1 insertString:@"...xyz" atIndex:3];
NSLog(@"%@", mutableString1);
//输出：abc...xyz
//替换
[mutableString1 replaceCharactorsInRange:NSMakeRange(0,3) withString:@"efg"];
NSLog(@"%@", mutableString1);
//输出：efg...xyz
//删除
[mutableString1 deleteCharactorsInRange:NSMakeRange(0,3)];
NSLog(@"%@", mutableString1);
//输出：...xyz
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