#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {
@autoreleasepool {
//创建
NSString *str1 = @"abc";
NSLog(@"%p", str1);
// str1 = [[NSString alloc] initWithString:@"abc"];
// NSLog(@"%p", str1);
//1. 将C语言字符串转化为OC的字符串对象,只能是UTF-8编码
str1 = [[NSString alloc] initWithUTF8String:"abc"];
//2. 支持更多编码
str1 = [[NSString alloc] initWithCString:"abc" encoding:NSUTF8StringEncoding];
int money = 10;//我有10块钱
//3. 格式化字符, NSLog()
str1 = [[NSString alloc] initWithFormat:@"我有%d块钱", money];
//4. 类方法
str1 = [NSString stringWithUTF8String:"abc"];
//5. 所有以名词开头的都会有返回值
str1 = [NSString stringWithFormat:@"我有%d块钱", money];
NSError *error;
//6. 将文本文件内容读取到字符串对象中,并将首地址保存到str1里
str1 = [NSString stringWithContentsOfFile:@"/Users/apple/Desktop/test.txt" encoding:NSUTF8StringEncoding error: &error];
if (error != nil) {
NSLog(@"%@", error);
}
else {
NSLog(@"%@", str1);
}
str1 = @"ab";
//7. 如果文件不存在,创建并保存内容;如果存在的话,覆盖
[str1 writeToFile:@"/Users/apple/Desktop/test2.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];
//8. 将基本数据类型(C类型)转化为OC的对象
str1 = [NSString stringWithFormat:@"%d", 123];
NSLog(@"%@", str1);
int value = str1.intValue;
NSLog(@"%d", value);
//9. 比较
// @"abc", @"abd"
// NSComparisonResult res = [@"abc" compare:@"abd"];
NSString *path = @"www.baidu.com";
//10. 检查前缀
if (![path hasPrefix:@"http://"]) {
path = [NSString stringWithFormat:@"http://%@", path];
}
NSLog(@"%@", path);
//11. 检查后缀
NSString *filename = @"1.jpg";
if ([filename hasSuffix:@".jpg"]) {
NSLog(@"这是一张jpg图片");
}
//12. 在一个字符串后添加一个字符串, 产生一个新的字符串,老的不变
NSString *str2 = [str1 stringByAppendingString:@"1111"];
NSLog(@"%@", str1);
NSLog(@"%@", str2);
str2 = [str1 stringByAppendingFormat:@"%d", 998];
NSLog(@"%@", str2);
NSString *desk = @"/Users/apple/Desktop";
for (int i = 1; i < 11; i++) {
NSLog(@"%@", [desk stringByAppendingFormat:@"/%d.txt", i]);
}
//13. 文件路径,自动添加分隔符
str2 = [desk stringByAppendingPathComponent:@"1.txt"];
NSLog(@"%@", str2);
str2 = [desk stringByAppendingPathExtension:@"exe"];
NSLog(@"%@", str2);
NSArray *array = [str2 pathComponents];
NSLog(@"%@", [array lastObject]);
filename = [array lastObject];
//删除扩展名
filename = [filename stringByDeletingPathExtension];
NSLog(@"filename: %@", filename);
//CSV
NSString *values = @"1,2;3";
// array = [values componentsSeparatedByString:@",;"];
//用@",;"里的字符生成一个字符的集合
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@",;"];
//使用字符集set中的字符分割字符串
array = [values componentsSeparatedByCharactersInSet:set];
NSLog(@"%@", array);
str1 = @"def教育abc";
NSLog(@"字符个数: %lu", str1.length);
NSLog(@"字节长度: %lu", [str1 lengthOfBytesUsingEncoding:NSUTF8StringEncoding]);
unichar c = [str1 characterAtIndex:0];
NSLog(@"%hu", c);
// const char *cstr = [str1 UTF8String];
// NSLog(@"cstr: %s", cstr);
str1 = @"abcdefghijk";
//将字符串扩充到10个字节,如果超过10个,裁剪
str1 = [str1 stringByPaddingToLength:10 withString:@".+-" startingAtIndex:2];
NSLog(@"%@", str1);
str1 = @"abcd zhang san aaaabcabc";
//裁剪首尾的字符
str1 = [str1 stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"zd abc"]];
NSLog(@"|%@|", str1);
str1 = @"01234567890";
//获取一个字串[3, 11)
str2 = [str1 substringFromIndex:3];
NSLog(@"%@", str2);
//[0, 3)
str2 = [str1 substringToIndex:3];
NSLog(@"%@", str2);
//截取一个范围内的字串
NSRange range = NSMakeRange(0, 5);//{0, 3};
str2 = [str1 substringWithRange:range];
NSLog(@"%@", str2);
str1 = @"world hello world";
//查找一个字串的位置, 默认为从左到右的第一个
range = [str1 rangeOfString:@"world"];
NSLog(@"{%lu, %lu}", range.location, range.length);
//没有找到,返回NSNotFound
if (range.location == NSNotFound) {
NSLog(@"没找到");
}
//将字符串中出现的world全部替换为hi
str2 = [str1 stringByReplacingOccurrencesOfString:@"world" withString:@"hi"];
NSLog(@"%@", str2);
str1 = @"hi, China";
//大写
str2 = str1.uppercaseString;
NSLog(@"%@", str2);
//小写
str1 = str2.lowercaseString;
NSLog(@"%@", str1);
//首字母大写
str2 = str1.capitalizedString;
NSLog(@"%@", str2);
NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
NSString *content = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
NSLog(@"%@", content);
[content writeToFile:@"/Users/apple/Desktop/index.html" atomically:YES encoding:NSUTF8StringEncoding error:nil];
str1 = @“教育";
//百分号转义
str2 = [str1 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSLog(@"%@", str2);
}
return 0;
}