+(NSString *)convert:(NSString *)str { //处理异常情况 if (str.length<=0) { NSLog(@"要反转的字符串为空"); return nil; } //初始化一个可变的字符串 NSMutableString *convert=[[NSMutableString alloc] initWithString:str]; for (int i=0; i<str.length; i++) { //获取字符串的一个字符,再构造成一个字符串对象 NSString *one=[[NSString alloc] initWithFormat:@"%c",[str characterAtIndex:str.length-i-1]]; //可变字符串的replace [convert replaceCharactersInRange:NSMakeRange(i, 1) withString:one]; } return convert; }
+(int)count:(NSString *)str { //处理异常情况 if (str.length<=0) { NSLog(@"要反转的字符串为空"); return nil; } int count=0; //循环遍历这个字符串如果字符是英文字母则count加1 for (int i=0; i<str.length; i++) { //获取字符串的字符 if (([str characterAtIndex:i]>='a'&&[str characterAtIndex:i]<='z')|| ([str characterAtIndex:i]>='A'&&[str characterAtIndex:i]<='Z')) { count++; } } return count; }
+(NSString *)disblank:(NSString *)str { int len=str.length;; //处理异常情况 if (len<=0) { NSLog(@"要反转的字符串为空"); return nil; } NSMutableString *disblank=[[NSMutableString alloc] initWithString:str]; //如果字符串第一个字符为空格则去掉空格 if([str characterAtIndex:0]==' ') { [disblank deleteCharactersInRange:NSMakeRange(0, 1)]; len--; } //如果字符串最后一个字符为空格则去掉空格 if ([str characterAtIndex:str.length-1]==' ') { //可变字符串的删除字符功能 [disblank deleteCharactersInRange:NSMakeRange(len-1, 1)]; } return disblank; }
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