关于字符串NSString 数组NSArray 字典NSDictionary的学习，本文主要以代码的形式展示了其一些常用的方法，掌握这些方法便可以对字符串 数组 字典有个大致的掌握。
[代码展示]
======字符串＝＝＝＝＝＝
#import <Foundation/Foundation.h>
int main(int argc, const char * argv[])
{
@autoreleasepool
{
//1. stringWithFormat
int age = 5;
NSString *string = [NSString stringWithFormat:@"我的年龄是%d", age];
NSLog(@"%@", string);
//2.c字符串转换为oc字符串
char *p = "abc";
NSString *ocString = [NSString stringWithCString:p encoding:NSUTF8StringEncoding];
NSLog(@"%@", ocString);
//3.length
NSString *one = @"ddd";
NSLog(@"%lu", one.length);
NSString *a = @"abc";
NSString *b = @"abc";
NSString *c = [NSString stringWithFormat:@"abc"];
if (a == b) // a和b指向常量池内同一块空间，地址相同 ，比较的不是内容，比较的是地址
{
NSLog(@"a == b");
}
if (a == c)
{
NSLog(@"a == c");
}
if ([a isEqualToString:c])
{
NSLog(@"a equal c");
}
NSString *d = @"abc";
NSLog(@"%ld", [d compare:a]);
NSString *fileName = @"iOS_45.doc";
if ([fileName hasPrefix:@"iOS"])
{
NSLog(@"");
}
if ([fileName hasSuffix:@".doc"])
{
NSLog(@"");
}
NSRange range = [fileName rangeOfString:@"456"]; // 找不到时
NSLog(@"%lu, %lu", range.location, range.length);
/*
NSString *s = [fileName uppercaseString]; // 返回转换后的字符串，不会改变原字符串内容 NSString为不可变字符串
NSLog(@"%@, %@", fileName, s);
NSLog(@"%p", fileName);
fileName = [fileName uppercaseString]; // 指向了新的字符串，
NSLog(@"%@", fileName);
NSLog(@"%p", fileName);
NSMutableString *mString = [NSMutableString stringWithFormat:@"abcdefghijklmnopqrstuvwxyz"];
// NSMutableString *mm = [NSMutableString stringWithCapacity:10]; // 容量是10，存10个字符串时效率最高
[mString appendString:@"opq"];
NSLog(@"%@", mString);
[mString insertString:@"ffff" atIndex:3];
NSLog(@"%@", mString);
NSRange range1 = NSMakeRange(0, 1);
[mString deleteCharactersInRange:range1]; // 删除
NSLog(@"%@", mString);
[mString replaceCharactersInRange:range1 withString:@"123"]; // 替换
NSLog(@"%@", mString);
[mString substringWithRange:range1]; // 截取
NSLog(@"%@", mString);
// 将不可变String转换成可变字符串
NSString *name = @"张三";
NSMutableString *mname = [name mutableCopy];
[mname replaceCharactersInRange:range1 withString:@"123"]; // 替换
NSLog(@"%@", mname);
*/
}
return 0;
}
＝＝＝＝＝＝数组＝＝＝＝＝＝
＝＝Student类的声明＝＝
#import <Foundation/Foundation.h>
@interface Student : NSObject
@property (strong, nonatomic) NSString *name;
@property (assign, nonatomic) int age;
-(instancetype) initStudentWithName:(NSString *)vname Age:(int)vage;
-(NSComparisonResult) compare:(Student *) other;
@end
＝＝Student类的实现＝＝
#import "Student.h"
@implementation Student
-(instancetype)initStudentWithName:(NSString *)vname Age:(int)vage
{
if (self = [super init])
{
self.name = vname;
self.age = vage;
}
return self;
}
-(NSComparisonResult)compare:(Student *)other
{
return [self.name compare:other.name];
}
@end
＝＝＝＝＝＝main＝＝＝＝＝＝
#import <Foundation/Foundation.h>
#import "Student.h"
int main(int argc, const char * argv[])
{
@autoreleasepool
{
// 只能存对象，不能存基本数据类型
NSArray *array1 = @[@"one", @"two", @"three"]; // 提倡第一种方式
// NSArray *array2 = [NSArray arrayWithObjects:@"one", @"two", @"three", nil];
for (int i = 0; i < array1.count; i++)
{
NSString *s1 = array1[i];
NSString *s2 = [array1 objectAtIndex:i];
NSLog(@"%@, %@", s1, s2);
}
// NSMutableArray 是 NSArray子类
// NSMutableArray *marray1 = [NSMutableArray arrayWithCapacity:10]; // 空的数组
NSMutableArray *marray2 = [NSMutableArray arrayWithObjects:@"one", @"two", @"three", nil];
// 添加
[marray2 addObject:@"123"];
NSLog(@"%@", marray2);
// 快速枚举
for (id sub in marray2)
{
NSLog(@"%@", sub);
}
NSLog(@"===============");
// 删除
[marray2 removeObjectAtIndex:1];
for (id sub in marray2)
{
NSLog(@"%@", sub);
}
NSLog(@"===============");
// 替换
[marray2 replaceObjectAtIndex:1 withObject:@"3"];
for (id sub in marray2)
{
NSLog(@"%@", sub);
}
NSLog(@"===============");
// 插入
[marray2 insertObject:@"1" atIndex:2];
for (id sub in marray2)
{
NSLog(@"%@", sub);
}
NSLog(@"===============");
// 排序
Student *s1 = [[Student alloc] initStudentWithName:@"张e三" Age:12];
Student *s2 = [[Student alloc] initStudentWithName:@"李四" Age:15];
Student *s3 = [[Student alloc] initStudentWithName:@"王五" Age:14];
NSMutableArray *stds = [NSMutableArray arrayWithCapacity:3];
[stds addObject:s1];
[stds addObject:s2];
[stds addObject:s3];
// 1 通过排序描述对象完成排序
NSSortDescriptor *desc = [NSSortDescriptor sortDescriptorWithKey:@"age" ascending:NO];
[stds sortUsingDescriptors:@[desc]];
for (id std in stds)
{
NSLog(@"name=%@, age=%d", [std name], [std age]);
}
NSLog(@"===============");
// 2 通过代码块的方式完成排序
[stds sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
if ([obj1 age] < [obj2 age])
{
return -1;
}
if ([obj1 age] > [obj2 age])
{
return 1;
}
return 0;
}];
for (id std in stds)
{
NSLog(@"name=%@, age=%d", [std name], [std age]);
}
NSLog(@"===============");
[stds sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {
return [[obj1 name] compare:[obj2 name]];
}];
for (id std in stds)
{
NSLog(@"name=%@, age=%d", [std name], [std age]);
}
NSLog(@"===============");
// 3 通过对象的排序方法完成排序
[stds sortUsingSelector:@selector(compare:)];
for (id std in stds)
{
NSLog(@"name=%@, age=%d", [std name], [std age]);
}
NSLog(@"===============");
}
return 0;
}
＝＝＝＝＝＝字典＝＝＝＝＝＝
#import <Foundation/Foundation.h>
int main(int argc, const char * argv[])
{
@autoreleasepool
{
// 字典的使用
// 包装 将基本的数据类型包装成对象
NSNumber *num1 = [NSNumber numberWithInt:12];
NSDictionary *dic = @{@"name":@"张三", @"age":num1};
// NSDictionary *dic1 = [NSDictionary dictionaryWithObjectsAndKeys:@"张三", @"name", num1, @"age", nil];
// 遍历字典
// 1 得到所有的key
NSArray *keys = [dic allKeys];
for (id key in keys)
{
id number1 = dic[key]; // 提倡用这种方式
// id number2 = [dic valueForKey:key];
if ([key isEqualToString:@"name"])
{
NSLog(@"%@", (NSString *) number1);
}
else
{
// 拆箱 获得number对象所存储的基本数据类型
NSNumber *n = (NSNumber *) number1;
NSLog(@"%d", [n intValue]);
}
}
// 2 快速枚举 相当于在字典的key中做遍历，得到所有的key
for (id key in dic)
{
NSLog(@"%@", dic[key]);
}
#pragma mark
// NSMutableDictionary
///////////////////////////////////////////////
NSDictionary *s1 = @{@"sid":@"1", @"sname":@"张三", @"sage":@"12", @"sex":@"男"};
NSDictionary *s2 = @{@"sid":@"2", @"sname":@"李四", @"sage":@"13", @"sex":@"女"};
NSDictionary *s3 = @{@"sid":@"3", @"sname":@"王五", @"sage":@"13", @"sex":@"男"};
NSMutableArray *array = [NSMutableArray arrayWithCapacity:3];
[array addObject:s1];
[array addObject:s2];
[array addObject:s3];
/*
类 Tool
+(Dictionary *) dictionary for URL :(NSString *) url;
截出字符串
按某一个符号分割
+
*/
}
return 0;
}
＝＝＝＝＝＝运行结果＝＝＝＝＝＝
张三
12
张三
12