How to form a dict out of a string by doing regex ?

[Satyajit Sarangi]

data = "GEOMETRYCOLLECTION (POINT (-8.9648437500000000
-4.1308593750000000), POINT (2.0214843750000000 -2.6367187500000000),
POINT (-1.4062500000000000 -11.1621093750000000), POINT
(-11.9531250000000000,-10.8984375000000000), POLYGON
((-21.6210937500000000 1.8457031250000000,2.4609375000000000
2.1972656250000000, -18.9843750000000000 -3.6914062500000000,
-22.6757812500000000 -3.3398437500000000, -22.1484375000000000
-2.6367187500000000, -21.6210937500000000
1.8457031250000000)),LINESTRING (-11.9531250000000000
11.3378906250000000, 7.7343750000000000 11.5136718750000000,
12.3046875000000000 2.5488281250000000, 12.2167968750000000
1.6699218750000000, 14.5019531250000000 3.9550781250000000))"

This is my string .
How do I traverse through it and form 3 dicts of Point , Polygon and
Linestring containing the co-ordinates ?

 

[Mel]

data = "GEOMETRYCOLLECTION (POINT (-8.9648437500000000
-4.1308593750000000), POINT (2.0214843750000000 -2.6367187500000000),
POINT (-1.4062500000000000 -11.1621093750000000), POINT
(-11.9531250000000000,-10.8984375000000000), POLYGON
((-21.6210937500000000 1.8457031250000000,2.4609375000000000
2.1972656250000000, -18.9843750000000000 -3.6914062500000000,
-22.6757812500000000 -3.3398437500000000, -22.1484375000000000
-2.6367187500000000, -21.6210937500000000
1.8457031250000000)),LINESTRING (-11.9531250000000000
11.3378906250000000, 7.7343750000000000 11.5136718750000000,
12.3046875000000000 2.5488281250000000, 12.2167968750000000
1.6699218750000000, 14.5019531250000000 3.9550781250000000))"

This is my string .
How do I traverse through it and form 3 dicts of Point , Polygon and
Linestring containing the co-ordinates ?

Except for those space-separated number pairs, it could be a job for some
well-crafted classes (e.g. `class GEOMETRYCOLLECTION ...`, `class POINT
....`) and eval.

My approach would be to use a loop with regexes to recognize the leading
element and pick out its arguments, then use the string split and strip
methods beyond that point. Like (untested):

recognizer = re.compile (r'(?(POINT|POLYGON|LINESTRING)\s*\(+(.*?)\)+,(.*)')
# regex is not good with nested brackets,
# so kill off outer nested brackets..
s1 = 'GEOMETRYCOLLECTION ('
if data.startswith (s1):
data = data (len (s1):-1)

while data:
match = recognizer.match (data)
if not match:
break # nothing usable in data
## now the matched groups will be:
## 1: the keyword
## 2: the arguments inside the smallest bracketed sequence
## 3: the rest of data
## so use str.split and str.match to pull out the individual arguments,
## and lastly
data = match.group (3)

This is all from memory. I might have got some details wrong in recognizer.

Mel.

 

[Terry Reedy]

data = "GEOMETRYCOLLECTION (POINT (-8.9648437500000000
-4.1308593750000000), POINT (2.0214843750000000 -2.6367187500000000),
POINT (-1.4062500000000000 -11.1621093750000000), POINT
(-11.9531250000000000,-10.8984375000000000), POLYGON
((-21.6210937500000000 1.8457031250000000,2.4609375000000000
2.1972656250000000, -18.9843750000000000 -3.6914062500000000,
-22.6757812500000000 -3.3398437500000000, -22.1484375000000000
-2.6367187500000000, -21.6210937500000000
1.8457031250000000)),LINESTRING (-11.9531250000000000
11.3378906250000000, 7.7343750000000000 11.5136718750000000,
12.3046875000000000 2.5488281250000000, 12.2167968750000000
1.6699218750000000, 14.5019531250000000 3.9550781250000000))"

This is my string .

If this what you are given by an unchangable external source or can you
get something a bit better? One object per line would make the problem
pretty simple, with no regex required.

How do I traverse through it and form 3 dicts of Point , Polygon and
Linestring containing the co-ordinates ?

Dicts map keys to values. I do not see any key values above. It looks
like you really want three sets.