Hello,
Searching the archives with "two dimensional array last" returned no hits.
I need to find the last tuple from this kind of output:
[[2.3110949921647266, 48.81514649393979], [2.3113524842301563, 48.815923619981966], …[2.28392243385315, 48.84728589885864], [2.2819232977235515, 48.84809311844251]]
Is there a better way than this?
first = track['geometry']['coordinates'][0]
#BAD last = track['geometry']['coordinates'][-1]
#BAD last = track['geometry']['coordinates'].keys()[-1]
#BAD last = track['geometry']['coordinates'].count()
sizearray = len(track['geometry']['coordinates'])
print(track['geometry']['coordinates'][sizearray-1])
Thank you.
What is the result of
print(type(track['geometry']['coordinates']))
?
in Python you can use negative indexes
just
print(track['geometry']['coordinates'][-1])
by the way, this is list of lists, not lists of tuples. Although they look pretty much the same, lists are mutable, and tuples are not.
this is list
[1, 2, 3]
and this is tuple
(1, 2, 3)
Thanks for the info about list of lists vs. list of tuples.
>> print(type(track['geometry']['coordinates']))
<class 'list'>
>> print(track['geometry']['coordinates'][-1])
[2.2819232977235515, 48.84809311844251]
Odd: This time, "[-1]" worked
In the original post:
#BAD last = track['geometry']['coordinates'][-1]
It returned an error, which is why I used the less elegant "sizearray-1".
Maybe it was a typo I didn't catch.
Another issue I came accross: In the JSON input file, most of the tracks are LineString, but a few of them are crappy Multilinestring (I guess the user's GPS burped at that point), so the code breaks because it ends up querying Nominatim with wrong data:
INPUT
GOOD : [2.3646783828735356, 48.844165146100025]
BAD : [[2.378497123718262, 48.85067473135253], [2.376008033752442, 48.85138776898278]]
import geojson
from geopy.geocoders import Nominatim
…
coords = track['geometry']['coordinates'][0]
#Flip coords: Nominatim expects lat, lon
coords = coords[::-1]
location = "{}, {}".format(coords[0], coords[1])
geolocator = Nominatim(user_agent="my-application",timeout=3)
location = geolocator.reverse(location)
try:
return(location.raw['address']['town'])
except KeyError:
return(location.raw['address']['city'])In this particular case, it doesn't matter if there's a straight line all of a sudden between two coords, so, as a work-around, I was wondering if there's a way to turn Multilinestring into Linestring?
Can you show small input file in full, with both good and bad data. LineString, MultilineString???
if you have list(array) of coordinates which one is the correct, according to you?