deleting certain rows from multidimensional list

[DeaD_EyE]

Your sample data:

csv_string='''type;latitude;longitude;speed
T;37.547575;15.143184;0.963040
T;37.547569;15.143185;0.833400
T;37.547565;15.143186;0.351880
T;37.547561;15.143194;0.629680
T;37.547560;15.143205;1.129720
T;37.547561;15.143222;1.259360
T;37.547562;15.143236;1.129720'''

The order of steps in your program:

1. Read a line
   
2. Convert data of the line
   
3. Make decision if data is in boundaries
   
4. If data is in boundaries -> yield data
   

Just as an example, don't use this code:

import csv
from functools import partial
import io


def in_boundaries(lat, lon, lat_min, lat_max, lon_min, lon_max):
    return lat_min < lat < lat_max and lon_min < lon < lon_max 

# your boundaries
boundaries = {
    'lat_min': 37.547560,
    'lat_max': 37.547570,
    'lon_min': 15.143184,
    'lon_max': 15.143186,
    }

# functional approach, using keyword unpacking
my_boundaries = partial(in_boundaries, **boundaries)


csv_string = '''type;latitude;longitude;speed
T;37.547575;15.143184;0.963040
T;37.547569;15.143185;0.833400
T;37.547565;15.143186;0.351880
T;37.547561;15.143194;0.629680
T;37.547560;15.143205;1.129720
T;37.547561;15.143222;1.259360
T;37.547562;15.143236;1.129720'''

file_like_csv = io.StringIO(csv_string)

reader = csv.reader(file_like_csv, delimiter=';')
header = next(reader)
#print(header)

for row in reader:
    # the part where you split your row into columns
    try:
        type, latitude, longitude, speed = row
    except ValueError:
        print('Invalid column length:', row)
        continue
    try:
        # convert lat, lon to float
        latitude, longitude = map(float, [latitude, longitude])
    except ValueError:
        print('Wrong value in:', row)
        continue
    # now decide if your data is in your defined boundary
    if my_boundaries(latitude, longitude):
        print(row)
        # here you should do something with your valid data
    else:
        # you don't need this.
        # this is just for control
        # print('Not in boundary:', row)
        pass

At the end it's very easy. Make a function which decides if your data is in your boundaries and do something with it.
No need to make this strange nested iteration.

What you need to know:

• Exception handling
  
• argument unpacking
  
• keyword argument unpacking, if you're working with dicts. Not necessary.
  
• functions
  
• use of csv module
  
• knowledge of iterables, csv.reader is an iterator
  
• comparison with more than one value (min_val < val < max_val)
  
• logical operations: and, or, not