一.不可变字符串的方法
创建字符串
NSString *str0 = [[NSString alloc]init];
//简单创建字符传
NSString *str1 = @"skdjfksjdklfs";
//对象方法创建字符传
NSString *str2 = [[NSString alloc]initWithString:str1];
//通过C语言中字符串创建OC语言中字符串
char strc[20] = "this is the test ";
NSString *str3 = [[NSString alloc]initWithUTF8String:str];
//通过类创建字符串
NSString *str4 = [NSString stringWithString:str1];
NSString *str5 = [NSString stringWithUTF8String:strc];
NSString * str6 = [NSString stringWithFormat:@"%@",str1];
从本地文件获取字符串
NSString *path = @"Users/File";
NSString *string = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:/*&error*/nil];
从网络中获取
NSURL *url = [NSURL URLWithString:@"http://www.baidu.com"];
NSString *string = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
字符串拼接
NSString *str1 = @"skjdhjkshfkdsss";
NSString *str2 = [str1 stringByAppendingString :@"!"];
字符串长度
NSString *str = @"ghjkl;ksjhdfsidhfs";
unsigned long len = [str length];
取其中一个字符串
char c = [str1 characterAtIndex: 2];
比较连个字符串大小
NSString *str1 = @"skjdhjkshfkdsss"; NSString *str2 = @"skjdhjkshfksdlfjsfdsss"; NSComparisonResult result = [str1 compare:str2];
if (result == NSOrderedAscending) {
NSLog(@"str1 < str2");
} else if (result== NSOrderedDescending){
NSLog(@"str1 > str2");
}else{
NSLog(@"str1 = str2");
}
大小写转换
NSString *string = @"jsjsdjk sdhfjksj sjdf";
NSString *str = [string lowercaseString];
NSString *str = [string uppercaseString];
NSSting *str = [string capitalizedString];
查找字符串
NSRange range = [string rangeOfString:@"jsdjk"];
if (range.location == NSNotFound){
//没有找到
} else {
}
if(range.length == 0){
//没有找到 如果找到了 length 就是要查找字符串的长度
}
//从右往左查
NSRange rangeFront = [string rangOfString:@"sdk"option:NSBackwardsSearch];
//判断前后缀
Bool isS = [str hasSuffix];
Bool isP = [str hasPrefix];
//将字符串转成数字
int num = [@"123" intValue];
//提取字符串 确定起始位置
NSString *str = [@"skjdo lskdl lsl" substringFromIndex:2];
//确定结束位置
NSString *str = [string6 substringToIndex:5];
//确定其实下标和结束位置（长度）
NSString *str = [@"dskj" substringWithRange:NSMakeRange(1, 2)];
二.可变字符串的方法
//创建空字符串
NSMutableString *muStr = [[NSMutableString alloc]init];
//capacity 表示的是一个大致范围
NSMutableString *str = [[NSMutableString alloc]initWithCapacity:10];
//可变字符串不能用此种方法创建 如果使用了 就是不可变字符串
NSString *string = @"sdjksd";
//通过对象方法创建可变字符传
NSMutableString *str1 = [[NSMutableString alloc]initWithString:@"yes"];
NSMutableString *str3 = [[NSMutableString alloc] initWithFormat:@"%@",str];
//通过类方法创建可变字符串
NSMutableString *muStr21 = [NSMutableString stringWithString:@"sds"];
NSMutableString *mutStr33 = [NSMutableString stringWithFormat:@"%@",string];
//通过本地文件
NSMutableString *mut223 = [NSMutableString stringWithContentsOfURL:@"/Users/01-字符串/File" encoding:NSUTF8StringEncoding error:nil];
//通过网络
NSMutableString *mutStr9 = [NSMutableString stringWithContentsOfURL:[NSURL URLWithString:@"http://www.baidu.com"] encoding:NSUTF8StringEncoding error:nil];
可变字符串增 字符串
NSMutableString *mut = [NSMutableString stringWithString:@"sjhdj sihfsdiu"];
[mut1 appendString:@"sdkjf"];
[mut1 appendFormat:@"dsfsds"];
//在任意位置添加
[mut1 insertString:@"sdfs" atIndex:2];
//删除任意位置字符串
NSMutableString mut = [NSMutableString stringWithString:@"sdkjfsdk"];
[mut deleteCharactersInRange:NSMakeRange(8, 8)];
//修改字符串
NSMutableString *mut5 = [NSMutableString stringWithString:@"sd sjd skjdf"];
//直接用后面的字符串替代现有的字符串
[mut5 setString:@"sdkfsf"];
//用存在的字符串替换选中位置的字符串
[mut5 replaceCharactersInRange:NSMakeRange(2, 2) withString:@"sdsf"];
//查
NSMutableString *mut6 = [NSMutableString stringWithString:@"sun is a girl "];
for (int i= 0; i< [mut6 length]; i++) {
char s = [mut6 characterAtIndex:i];
}
将字符串funnel与字符串also之间的字符串提取出来，不可以数
NSString *string = @"NSString primitive (funnel) methods. A minimal subclass of NSString just needs to implement these, although we also recommend";
NSRange range1 = [string rangeOfString:@"funnel"];
NSRange range2 = [string rangeOfString:@"also"];
NSRange range = NSMakeRange(range1.location + range1.length, range2.location - range1.location - range1.length);
NSString *subString = [string substringWithRange:range];
NSLog(@"*%@*", subString);
