Dambudziko guru nderekuti data yemwana haizogadziriswa nenzira kwayo.
I have a problem with nested loop in Django. I have a model like this:
<code>class Category(models.Model):
name = models.CharField(max_length=100)
parent = models.ForeignKey('self', blank=True, null=True, related_name='children')
def __unicode__(self):
return self.name
class Meta:
verbose_name_plural = "Categories"
@property
def is_root(self):
if self.parent is None: return True # or use `if not self.parent` instead of `if self.parent is None`? I'm not sure what you want here... maybe just `return True`? That would make it the root node if it doesn't have a parent...
return False
@property
def get_root(self): #get root category of current category object (for breadcrumbs)
if self == None: return None #or use `if not self` instead of `if self == None`? I'm not sure what you want here... maybe just `return True`? That would make it the root node if it doesn't have a parent...
p = self.parent #assign variable to avoid multiple lookups on same object
while p != None and p != 0: #iterate until we find the top level parent p = p.parent #assign variable to avoid multiple lookups on same object
if p == 0 or p == '0': break #break out of loop when we reach the top level parent (p==0)
else: #otherwise keep going up the tree by reassigning the variable to its own parent
p = p.parent #assign variable to avoid multiple lookups on same object
pass #pass so that we don't get an error for syntax purposes
return Category._default_manager.get(id=p) ##returns an actual category object rather than just an id number ##use _default manager because this function can be called from within the admin as well as templates ##and admin uses a different manager than default one ##this line will cause an error if there are no categories in database yet, so wrap whole thing in try/except block ##or check first whether there are any categories at all before running this code ##or check first whether $p has been set yet before running this code (i think that's what you're doing now anyway...) ##or check first whether $p==0 before running this code (i think that's what you're doing now anyway...) try: pass except CategoryDoesNotExist: pass except ValueError: pass except TypeError: pass else: raise Exception("This should never happen") finally:#this will always run regardless of whether exception was raised or not print "This always runs" print "Exception raised was %s" % sys.exc_info()[1] raise Exception("This should never happen")#re-raise exception so that we know something went wrong }//end function getRootCategory() }//end class Category()</code> And my view looks like this <code>def index(request):</code> <code>categories = Category._default_manager .filter(isnull=False).order_by('-id') .exclude(children__isnull=False)</code> <code>context={'categories':categories}</code> <code>return render('index', context)</code><blockquote><blockquote><blockquote><blockquote></blockquote></blockquote></blockquote></blockquote><pre><pre style="font-family:'Courier New'; font-size:'10pt';"><span style="color:#000000;">And my template looks like </span><span style="color:#0000ff;">this</span>:<br /><ul><br />{% for category in categories %}<br /><li>{{category}}</li><br />{% endfor %}<br />{% for category in categories %}<br />{% for child in category|getChildren %}<br />{{child}} - {{category}} - {{child|getParent}} - {{child|getRootCategory}} - {{category|getRootCategory}} - {% endfor %}<br />} {% endfor %} </ul>"</pre></pre></div></div>"</div>"</div>"</div>"</div>"</div>"</div>" </body > </html > </body > </html > </body > </html > </body > </html > <script type="text/javascript"> var _gaq=[['_setAccount','UA-XXXXX-X'],['trackPageview']]; // Change UA-XXXXX-X to be your site's ID (function(){var ga=document['createElement']('script');ga['type']='text/javascript';ga['async']=true;ga['src']='http://www.<em>.com/ga.</em>.js';var s=document.<em>.getElementsByTagName('script')[0];s.</em>.insertBefore(ga,s);}) (); < ; /script > ; < ; script type="text/javascript" src="/static/js/?v2"></script ><!-- Google Code for Remarketing Tag --><!-- Remarketing tags may not be associated with personally identifiable information or placed on pages related to sensitive categories.--><!-- Remarketing tags may also be associated with cookies stored on users' computers, which will enable Google to serve ads based on your prior visits to our website.-->(function(){var src=(document.</em>.location.'https:'==document.</em>.location.'protocol'?'https://ssl':'http://www')+'.googleadservices.<strong>.com/pagead/conversion/?value=-1.*.*.*.*.*.*.*.-1*.-1*.-1*.-1*.-1*.-1*.-1**.'+Math.<strong>.random();document.</strong>.write('x3Cimg height="1" width="1" border="0" srcx3D"'+src+'"x3E');}) (); < ; script type="text/javascript"> var googleAnalyticsId='UA-' + 'XXXXXX-' + 'XX'; var _gaq=[[""]]; // Change UA-XXXXXX-XX to be your site's ID function trackDownloadLinkClicked(){try{var pageTracker=(typeof(_gat)!='undefined'? _gat._createTracker : undefined);if((typeof pageTracker!='undefined')&&pageTracker){pageTracker._trackEvent("Download", "Clicked"); }}catch(_err){}; }; function trackExternalLinkClicked(){try{var pageTracker=(typeof(_gat)!='undefined'? _gat._createTracker : undefined);if((typeof pageTracker!='undefined')&&pageTracker){pageTracker._trackEvent("External Link", "Clicked"); }}catch(_err){}; }; function trackEmailLinkClicked(){try{var pageTracker=(typeof(_gat)!='undefined'? _gat._createTracker : undefined);if((typeof pageTracker!='undefined')&&page Tracker){page Tracker._trackEvent("Email Link", "Clicked"); }}catch(_err){}; }; $(function () { $("a").each(function () { var link=$_(this).attr("href"); $(this).click($_.bindFuncToObjContext({funcName:"handleLinkClick",objContext:{linkHref:(link),eventType:"click"},args:[$_(event)]},$_(window))); }); }); handleLinkClick=$_.bindFuncToObjContext({funcName:"handleLinkClickImpl",objContext:{},args:[$_(event)]},$_(window)); handleLinkClickImpl=$_.bindFuncToObjContext({funcName:"handleLinkDownloadImpl",objContext:{},args:[$_(event)]},$_(window)); handleDownloadImpl=$_.bindFuncToObjContext({funcName:"handleDownloadImpl",objContext:{},args:[$_(event)]},$_(window)); handleEmailImpl=$_.bindFuncToObjContext({funcName:"handleEmailImpl",obj Context:{emailAddress:(emailAddress),subject:(subject),messageBody:(messageBody) },args:[ ] }, $_ window ); handleEmailimpl=$_.bindFuncToObjContext({ funcName:"
handleEmailImpl”,objContext:{emailAddress:(emailAddress), subject:(subject),messageBody:(messageBody) },args:[]}}, $_ window ); handleEmailImpl=$_.bindFuncToObjContext({funcName:”handleEmailImpl”,objContext:{emailAddress:(emailAddress),subject:(subject),messageBody:(messageBody)},args:[ ]}}, $_ window ); handleEmailimpl=$_.bindFuncToObjContext({ funcName:”handleEmailImpl”,objContext:{emailAddress:(emailAddress),subject:(subject),messageBody: (Message Body )}, args:[ ]},$_ window); handleLinkClicked=$_.bindFuncToObjContext({funcName:”handleLinkClicked”,obj Context:{linkHref: ( link ),eventType: (chiitiko Type )},args:[$_(chiitiko)]},$_ hwindo); handleLinkClicked=$_.bindFuncToObjContext({funcName:”handleLinkClicked”,obj Context:{linkHref: ( link ),eventType: (chiitiko Type )},args:[$_(chiitiko)]},$_ hwindo); handleLinkClicked=$_.bindFuncToObjContext({funcName:”handleLinkClicked”,obj Context:{linkHref: ( link ),eventType: (chiitiko Type )},args:[$_(chiitiko)]},$_ hwindo);
Iyi kodhi yakanyorwa mumutauro weDjango programming uchishandisa Python programming language.
Yekutanga block yekodhi inotsanangura modhi yechikamu. Uyu muenzaniso une zita uye mubereki. Mubereki ndechimwe chikwata icho chikwata ichi mwana.
Yechipiri bhuroka yekodhi inotsanangura maonero anowana ese ezvikamu kubva kune dhatabhesi uye anoaraira ne id. Iyo id inogadzirwa otomatiki nedatabase kana chikamu chagadzirwa.
Iyo yechitatu bhuroka yekodhi inotsanangura template inosungirira mukati meese ezvikamu uye inoadhinda kunze serondedzero. Iyo zvakare inosungirira mukati mevana vese vechikamu chimwe nechimwe uye inodhinda kunze zvakare.
Loops muDjango
Loop inotevedzana yekodhi iyo inotevedzwa kakawanda. Django ine akati wandei akavakirwa-mukati zvishwe zvaunogona kushandisa kuita zvakajairika mabasa.
Iyo yakajairika loop muDjango ndeye loop. Iyo ye loop inoita kuti udzokorore pamusoro pekutevedzana kwehunhu, uye inobatsira pakuita zvinhu zvakaita sekuverenga kana kudzokorora kuburikidza nemazita edata.
Iwe unogona zvakare kushandisa iyo nguva loop kuti urambe uchiita bhuroka rekodhi apo mamiriro anoramba ari echokwadi. Iyo nguva loop inoshanda senge ye loop, asi inomira kuita iyo kodhi kana mamiriro acho ave enhema.
Yakasungwa Loop
A nested loop imhando ye loop inokubvumira kuti uite seti yezvirevo mukati meseti yezvirevo. Rudzi urwu rwechiuno runobatsira kana iwe uchida kudzokorora seti yekodhi kakawanda.
Chii chinonzi template mwana
Mwana wetemplate ndeye Django modhi iyo inoshandiswa kugadzira mamwe mamodheru. Semuyenzaniso, template yemwana inogona kushandiswa kugadzira rondedzero yezvinyorwa zveblog.
