Understanding the 'NoneType' Object has no attribute '__getitem__' Error in Python
Asked 2 years ago, Updated 2 years ago, 51 viewsHow on earth can we solve the error in the image?
As a result of the investigation, there seems to be a problem with the attributes, but I am not sure, so I asked you a question.
The source code is listed below.
Thank you for your cooperation.
import sys,getopt
import sqlite3
class Location:
def_init__(self, filename=""):
self.filename = filename
self.locations=list()
def seek (self):
if self.filename==":
return False
file=open(self.filename, "r")
For line in file:
line_sep = line.split("\t")
if(len(line_sep)>2):
if(line_sep[1]=="LOC"):
time=line_sep[2].split(',')[0]
latitude=line_sep[2].split(',')[1]
longitude=line_sep[2].split(',')[2]
location={'time':time, 'latitude':latitude, 'longitude':longitude}
self.locations.append(location)
return True
def printAll(self):
if(len(self.locations)>0):
print'time, latitude, longitude'
for location in self.locations:
print location ['time'], location ['latitude'], location ['longitude']
Class Audio:
def_init__(self, filename=""):
self.filename = filename
self.startTime = 0.0
self.stopTime = 0.0
def seek (self):
if self.filename==":
return False
file=open(self.filename, "r")
For line in file:
line_sep=line.split()
if(len(line_sep)>2):
if(line_sep[1]=="AUDIO"):
if(line_sep[2]=="start"):
self.startTime=line_sep[0]
elif(line_sep[2]=="stop"):
self.stopTime=line_sep[0]
return True
def printTime (self):
print self.startTime, self.stopTime
defaultDuration(self):
return(float(self.stopTime)-float(self.startTime))
Class FileManager:
def__init__(self, filename, database):
# database connection
self.conn=sqlite3.connect(database)
self.cur = self.conn.cursor()
self.filename = filename
# filename must be separated by '-'. (e.g.hasc-20120527-115511-raw.log)
self.idname='-'.join(filename.split("-")[0:3])
def_getFileinfoId(self):
self.cur.execute("select fileinfo.id from files inner join fileinfo on files.id=fileinfo.fileId where files.filename like'"+self.idname+"%')
return self.cur.fetphone() [0]
defaultDatabase(self):
fileinfoId=str(self._getFileinfoId())
audio=Audio(self.filename)
audio.seek()
self.cur.execute("update fileinfo set startTime='+audio.startTime+"'where id="+fileinfoId)
self.cur.execute("update fileinfo set endTime='+audio.stopTime+"'where id="+fileinfoId)
self.conn.commit()
loc=Location(filename=self.filename)
loc.seek()
for location in loc.locations:
self.cur.execute("insert into geolocations(fileId, time, latitude, longitude) values("+fileinfoId+", "+location['time']+", "+location['latitude']+", "+location['longitude']+")
self.conn.commit()
defmain(argv):
logfile='"
database='"
try:
opts, args=getopt.getopt(argv, "hl:d:", ["log=", "db="])
iflen(opts)<1:
raise getopt.GetoptError("")
except getopt.GetoptError:
print 'hascseeker.py --log<logfile>--db<databasefile>'
sys.exit()
for opt, argin opts:
if opt in ("-h", "--help"):
print 'hascseeker.py --log<logfile>--db<databasefile>'
sys.exit()
elifopt in ("-l", "--log"):
logfile=arg
elifopt in ("-d", "--db"):
database=arg
man = FileManager (logfile, database)
man.updateDatabase()
if__name__=="__main__":
main(sys.argv[1:])
2 Answers
If the SQL statement has zero results, fetphone() returns None.
11.13.sqlite3—DB-API 2.0 interface for SQLite databases
Cursor.fetphone()
Fetches the next row of a query result set, returning a single sequence, or None when no more data is available.
Therefore, it should be written as follows.
def_getFileinfoId(self):
self.cur.execute("select fileinfo.id from files inner join fileinfo on files.id=fileinfo.fileId where files.filename like'"+self.idname+"%')
result=self.cur.fetphone()
return (None if result is None else result [0])
However, in the case of None, I will return it as it is, so please change it accordingly.
If you look at heliac2001's answer, you don't seem to understand what the error means, so please understand the meaning of the error message a little.
'NoneType' object has no attribute'__getitem__'
Attribute can be translated as an attribute, but the meaning of this error is simply a method or property.
It means "(like calling _getitem__), but you don't have a method or property called _getitem__.
The first 'NoneType' object is an object of type None.The variable is (None, not letters or numbers).
To sum up (not so much),
"The line in question tries to use __getitem__ for a none-type object, but the object does not have anything called _getitem__"
This error is exactly the same as the following code.
sample=None
sample.__getitem__(0)
Now, the question arises as to where the _getitem__ that does not exist in the code came from, which is a special method Python calls internally (magic method).
When accessing container variables such as varname[0], python implicitly invokes the _getitem__ method (the magic method is usually not something that Python invokes internally, so the user can call it).
Python 2.7.8 (default, Jun 30 2014, 16:03:49) [MSC v.1500 32-bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>>a = ['x', 'y']
>>a [0]
'x'
>>>a.__getitem__(0)<-getitem can be retrieved in the same way.
'x'
>>b = {'a': 'A', 'b': 'B'}
>>b ['a']
'A'
>>>b.__getitem__('a')<-getitem can be obtained in the same way.
'A'
>>b.__getitem__('b')
'B'
_xxxx__ Imagine trying to start with a name if a style description appears in the error.
In self.cur.fetphone()[0], fetphone() returns None, so None[0] and there is an error trying to retrieve the 0th item from the None type.
I explained it, but it may not be easy to understand (^^;
)
If you have any answers or tips
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