以下代码适用于html页面中文本@property (assign, nonatomic) BOOL isMaxed;
@property (assign, nonatomic) MKCoordinateSpan lastDelta;
self.lastDelta = MKCoordinateSpanMake(0.006, 0.006);
- (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated {
if (mapView.mapType != MKMapTypeStandard && self.isMaxed) {
[self checkRegionWithDelta:self.lastDelta.longitudeDelta];
}
}
- (void)checkRegionWithDelta:(float)delta {
if (self.mapView.region.span.longitudeDelta < delta) {
MKCoordinateRegion region = self.mapView.region;
region.span = self.lastDelta;
[self.mapView setRegion:region animated:NO];
} else if (self.mapView.region.span.longitudeDelta > delta) {
self.isMaxed = NO;
}
}
- (void)mapViewDidFinishRenderingMap:(MKMapView *)mapView fullyRendered:(BOOL)fullyRendered {
if (mapView.mapType != MKMapTypeStandard && !self.isMaxed) {
[self checkToProcess:self.lastDelta.longitudeDelta];
}
}
- (void)checkToProcess:(float)delta {
if (self.mapView.region.span.longitudeDelta < delta) {
UIGraphicsBeginImageContext(self.mapView.bounds.size);
[self.mapView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *mapImage = UIGraphicsGetImageFromCurrentImageContext();
[self processImage:mapImage];
}
}
- (void)processImage:(UIImage *)image {
self.mapColor = [self averageColor:image];
const CGFloat* colors = CGColorGetComponents( self.mapColor.CGColor );
[self handleColorCorrection:colors[0]];
}
- (void)handleColorCorrection:(float)redColor {
if (redColor < 0.29) {
self.isMaxed = YES;
[self.mapView setRegion:MKCoordinateRegionMake(self.mapView.centerCoordinate, self.lastDelta) animated:YES];
} else {
self.lastDelta = self.mapView.region.span;
}
}
- (UIColor *)averageColor:(UIImage *)image {
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
unsigned char rgba[4];
CGContextRef context = CGBitmapContextCreate(rgba, 1, 1, 8, 4, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big);
CGContextDrawImage(context, CGRectMake(0, 0, 1, 1), image.CGImage);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);
if(rgba[3] > 0) {
CGFloat alpha = ((CGFloat)rgba[3])/255.0;
CGFloat multiplier = alpha/255.0;
return [UIColor colorWithRed:((CGFloat)rgba[0])*multiplier
green:((CGFloat)rgba[1])*multiplier
blue:((CGFloat)rgba[2])*multiplier
alpha:alpha];
}
else {
return [UIColor colorWithRed:((CGFloat)rgba[0])/255.0
green:((CGFloat)rgba[1])/255.0
blue:((CGFloat)rgba[2])/255.0
alpha:((CGFloat)rgba[3])/255.0];
}
}
的标记h2，例如https://www.hl7.org/fhir/valueset-account-status.html
"Content Logical definition"但对于以下不包含带有“＆＃34;内容逻辑定义＆＃34;”的网页，例如https://www.hl7.org/fhir/valueset-cpt-all.html会返回以下错误：
def extract_table(url):
r = requests.get(url)
soup = BeautifulSoup(r.content, 'lxml')
h2 = soup.find(lambda elm: elm.name == 'h2' and 'Content Logical Definition' in elm.text)
div = h2.find_next_sibling('div')
return div.find('table')
当网页中没有'NoneType' object has no attribute 'find_next_sibling'
时，如何编辑代码以返回非表格的代码。
答案 0 :(得分：2)
您可以通过两种常见方式实现：
h2 = soup.find(lambda elm: elm.name == 'h2' and 'Content Logical Definition' in elm.text)
return div.find_next_sibling('div').find('table') if h2 else None
EAFP - easier to ask for forgiveness than permission：
try:
h2 = soup.find(lambda elm: elm.name == 'h2' and 'Content Logical Definition' in elm.text)
div = h2.find_next_sibling('div')
return div.find('table')
except AttributeError:
return None