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iOS字符串处理笔记，包括如何使用正则表达式解析，NSScanner扫描，设置和使用CoreParse解析器来解析处理自定义符号等内容
- (NSRange)rangeOfString:(NSString *)aString options:(NSStringCompareOptions)mask range:(NSRange)searchRange locale:(NSLocale *)locale
-initWithFormat:
-initWithFormat:arguments:
+stringWithFormat:
uint64_t p = 2305843009213693951;
NSString *s = [NSString stringWithFormat:@"The ninth Mersenne prime is %llu", (unsigned long long) p];
// "The ninth Mersenne prime is 2305843009213693951"
| Modifier | d, i | o, u, x, X |
|---|---|---|
| hh | signed char | unsigned char |
| h | short | unsigned short |
| (none) | int | unsigned int |
| l(ell) | long | unsigned long |
| j | intmax_t | uintmax_t |
| t | ptrdiff_t | |
| z | size_t |
int m = -150004021;
uint n = 150004021U;
NSString *s = [NSString stringWithFormat:@"d:%d i:%i o:%o u:%u x:%x X:%X", m, m, n, n, n, n];
// "d:-150004021 i:-150004021 o:1074160465 u:150004021 x:8f0e135 X:8F0E135"
//o是八进制
int m = 42;
NSString *s = [NSString stringWithFormat:@"‘%4d‘ ‘%-4d‘ ‘%+4d‘ ‘%4.3d‘ ‘%04d‘", m, m, m, m, m];
// "[ 42] [42 ] [ +42] [ 042] [0042]"
m = -42;
NSString *s = [NSString stringWithFormat:@"‘%4d‘ ‘%-4d‘ ‘%+4d‘ ‘%4.3d‘ ‘%04d‘", m, m, m, m, m];
// "[ -42] [-42 ] [ -42] [-042] [-042]"
double v[5] = {12345, 12, 0.12, 0.12345678901234, 0.0000012345678901234};
NSString *s = [NSString stringWithFormat:@"%g %g %g %g %g", v[0], v[1], v[2], v[3], v[4]];
// "12345 12 0.12 0.123457 1.23457e-06"
NSString *s = [NSString stringWithFormat:@"%f %f %f %f %f", v[0], v[1], v[2], v[3], v[4]];
// "12345.000000 12.000000 0.120000 0.123457 0.000001"
NSString *limerick = @"A lively young damsel named Menzies
"
@"Inquired: «Do you know what this thenzies?»
"
@"Her aunt, with a gasp,
"
@"Replied: "It‘s a wasp,
"
@"And you‘re holding the end where the stenzies.
";
NSString *limerick = @"A lively young damsel named Menzies
Inquired: «Do you know what this thenzies?»
Her aunt, with a gasp,
Replied: "It‘s a wasp,
And you‘re holding the end where the stenzies.
";
NSString * string = @"The man " @"who knows everything " @"learns nothing" @".";
-deleteCharactersInRange:
-insertString:atIndex:
-replaceCharactersInRange:withString:
-replaceOccurrencesOfString:withString:options:range:
-stringByReplacingOccurrencesOfString:withString:
-stringByReplacingOccurrencesOfString:withString:options:range:
-stringByReplacingCharactersInRange:withString:
NSMutableString *string; // 假设我们已经有了一个名为 string 的字符串
// 现在要去掉它的一个前缀，做法如下:
NSString *prefix = @"WeDon’tWantThisPrefix"
NSRange r = [string rangeOfString:prefix options:NSAnchoredSearch range:NSMakeRange(0, string.length) locale:nil];
if (r.location != NSNotFound) {
[string deleteCharactersInRange:r];
}
NSArray *names = @["Hildr", @"Heidrun", @"Gerd", @"Guðrún", @"Freya", @"Nanna", @"Siv", @"Skaði", @"Gróa"];
NSString *result = [names componentsJoinedByString:@", "];
NSError *error = nil;
NSString *pattern = @"(\w+) = #(\p{Hex_Digit}{6})";
NSRegularExpression *expression = [NSRegularExpression regularExpressionWithPattern:pattern
options:0
error:&error];
NSTextCheckingResult *result = [expression firstMatchInString:string
options:0
range:NSMakeRange(0, string.length)];
NSString *key = [string substringWithRange:[result rangeAtIndex:1]];
NSString *value = [string substringWithRange:[result rangeAtIndex:2]];
将字符串分解成数组，使用componentsSeparatedByString:这个方法，或者enumerateSubstringsInRange:options:usingBlock:。如果是按照行来进行分解可以使用option这个参数传NSStringEnumerationByLines
NSString *input = @“
backgroundColor = #ff0000
textColor = #0000ff
"
NSString *pattern = @"(\w+) = #([\da-f]{6})";
NSRegularExpression *expression = [NSRegularExpression regularExpressionWithPattern:pattern
options:0
error:NULL];
NSArray *lines = [input componentsSeparatedByCharactersInSet:[NSCharacterSet newlineCharacterSet]];
NSMutableDictionary *result = [NSMutableDictionary dictionary];
for (NSString *line in lines) {
NSTextCheckingResult *textCheckingResult = [expression firstMatchInString:line
options:0
range:NSMakeRange(0, line.length)];
NSString* key = [line substringWithRange:[textCheckingResult rangeAtIndex:1]];
NSString* value = [line substringWithRange:[textCheckingResult rangeAtIndex:2]];
result[key] = value;
}
return result;
NSScanner *scanner = [NSScanner scannerWithString:string];
//默认情况下，扫描器会跳过所有空格符和换行符。但这里我们只希望跳过空格符
scanner.charactersToBeSkipped = [NSCharacterSet whitespaceCharacterSet];
//定义一个十六进制字符集
NSCharacterSet *hexadecimalCharacterSet =
[NSCharacterSet characterSetWithCharactersInString:@"0123456789abcdefABCDEF"];
NSMutableDictionary *result = [NSMutableDictionary dictionary];
while (!scanner.isAtEnd) {
NSString *key = nil;
NSString *value = nil;
NSCharacterSet *letters = [NSCharacterSet letterCharacterSet];
BOOL didScan = [scanner scanCharactersFromSet:letters intoString:&key] &&
[scanner scanString:@"=" intoString:NULL] &&
[scanner scanString:@"#" intoString:NULL] &&
[scanner scanCharactersFromSet:hexadecimalCharacterSet intoString:&value] &&
value.length == 6;
result[key] = value;
[scanner scanCharactersFromSet:[NSCharacterSet newlineCharacterSet]
intoString:NULL]; // 继续扫描下一行
}
return result;
- (NSDictionary *)parse:(NSString *)string error:(NSError **)error
{
self.scanner = [NSScanner scannerWithString:string];
self.scanner.charactersToBeSkipped = [NSCharacterSet whitespaceCharacterSet];
NSMutableDictionary *result = [NSMutableDictionary dictionary];
NSCharacterSet *letters = [NSCharacterSet letterCharacterSet]
while (!self.scanner.isAtEnd) {
NSString *key = nil;
UIColor *value = nil;
BOOL didScan = [self.scanner scanCharactersFromSet:letters intoString:&key] &&
[self.scanner scanString:@"=" intoString:NULL] &&
[self scanColor:&value];
result[key] = value;
[self.scanner scanCharactersFromSet:[NSCharacterSet newlineCharacterSet]
intoString:NULL]; // 继续扫描下一行
}
}
- (BOOL)scanColor:(UIColor **)out
{
return [self scanHexColorIntoColor:out] || [self scanTupleColorIntoColor:out];
}
//扫描设置#ff0000这样的
- (BOOL)scanHexColorIntoColor:(UIColor **)out
{
NSCharacterSet *hexadecimalCharacterSet =
[NSCharacterSet characterSetWithCharactersInString:@"0123456789abcdefABCDEF"];
NSString *colorString = NULL;
if ([self.scanner scanString:@"#" intoString:NULL] &&
[self.scanner scanCharactersFromSet:hexadecimalCharacterSet
intoString:&colorString] &&
colorString.length == 6) {
*out = [UIColor colorWithHexString:colorString];
return YES;
}
return NO;
}
- (BOOL)scanTupleColorIntoColor:(UIColor **)out
{
NSInteger red, green, blue = 0;
BOOL didScan = [self.scanner scanString:@"(" intoString:NULL] &&
[self.scanner scanInteger:&red] &&
[self.scanner scanString:@"," intoString:NULL] &&
[self.scanner scanInteger:&green] &&
[self.scanner scanString:@"," intoString:NULL] &&
[self.scanner scanInteger:&blue] &&
[self.scanner scanString:@")" intoString:NULL];
if (didScan) {
*out = [UIColor colorWithRed:(CGFloat)red/255.
green:(CGFloat)green/255.