python - json.dumps() can not convert a dict whose value is list -


when learn web crawler scrapy, , save data json. found json.dumps () can not work on list of values list,like this:

def __init__(self):     self.file = codecs.open("mydata2.json","wb",encoding="utf-8")  def process_item(self, item, spider):      line = json.dumps(i,ensure_ascii=false) + '\n'     print(line)     self.file.write(line)     return item def close_spider(self,spider):     self.file.close()

it doesn't work.then modify code

def __init__(self):     self.file = codecs.open("mydata2.json","wb",encoding="utf-8")  def process_item(self, item, spider):     = dict(item)     key in i.keys():         i[key] = str(i[key])     print(i)     line = json.dumps(i,ensure_ascii=false) + '\n'     print(line)     self.file.write(line)     return item def close_spider(self,spider):     self.file.close()

everything right.so how going?

maybe there data in origin type can not serialized. if convert string, can serialized.

you can define custom jsonencoder fix this.

to use custom jsonencoder subclass (e.g. 1 overrides default() method serialize additional types), specify cls kwarg; otherwise jsonencoder used.


Comments

Post a Comment

Popular posts from this blog

python - Operations inside variables -

this question has answer here: evaluating mathematical expression in string 12 answers i want make python script finds maximum possible output using 2 operations. problem says there syntax error @ 2nd last line, in b in there. how can fix it? x = 0 = int(input("1st number:")) c = int(input("2nd number:" )) e = int(input("3rd number:" )) in range(4): if == 0: b = "+" elif == 1: b = "-" elif == 2: b = "/" else: b = "*" j in range(4): if j == 0: d = "+" elif j == 1: d = "-" elif j == 2: d = "/" else: d = "*" k = b c d e print(k) if you're after variables e on single line, couldn...
Read more

Generic Map Parameter java -

i having lot of methods of type: public static list<eduusers> getdetails(class c, map<string, integer> params) { list<eduusers> details = null; session session = hibernateutil.getsessionfactory().opensession(); transaction tx = null; try { tx = session.begintransaction(); criteria cr = session.createcriteria(c); (map.entry<string, integer> entry : params.entryset()) { cr.add(restrictions.eq(entry.getkey(), entry.getvalue())); } details = cr.list(); tx.commit(); } catch (exception asd) { log.debug(asd.getmessage()); if (tx != null) { tx.commit(); } } { session.close(); } return details; } i trying have generic method them , have written far: public static <t> list<t> getdetails(class<t> c, class<t> b) { l...
Read more

arrays - What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? -

what arrayindexoutofboundsexception mean , how rid of it? here code sample triggers exception: string[] name = {"tom", "dick", "harry"}; for(int = 0; i<=name.length; i++) { system.out.print(name[i] +'\n'); } your first port of call should documentation explains reasonably clearly: thrown indicate array has been accessed illegal index. index either negative or greater or equal size of array. so example: int[] array = new int[5]; int boom = array[10]; // throws exception as how avoid it... um, don't that. careful array indexes. one problem people run thinking arrays 1-indexed, e.g. int[] array = new int[5]; // ... populate array here ... (int index = 1; index <= array.length; index++) { system.out.println(array[index]); } that miss out first element (index 0) , throw exception when index 5. valid indexes here 0-4 inclusive. correct, idiomatic for statement here be: for (int index = 0; index <...
Read more