How to group array of the same name using Python? -

i have on thousand array categories in text file, example:

category a1 , cateogry a2: (array in matlab code)

a1={[2,1,2]}; a1={[4,2,1,2,3]}; a2={[3,3,2,1]}; a2={[4,4,2,2]}; a2={[2,2,1,1,1]}; 

i use python me read file , group them into:

a1=[{[2,1,2]} {[4,2,1,2,3]}];   a2=[{[3,3,2,1]} {[4,4,2,2]} {[2,2,1,1,1]}]; 

use dict group, presume mean group strings not valid python containers coming .mat matlab file:

from collections import ordereddict od = ordereddict() open("infile") f:     line in f:         name, data = line.split("=")         od.setdefault(name,[]).append(data.rstrip(";\n"))  pprint import pprint pp pp((od.values())) [['{[2,1,2]}', '{[4,2,1,2,3]}'], ['{[3,3,2,1]}', '{[4,4,2,2]}', '{[2,2,1,1,1]}']] 

to group data in file write content:

with open("infile", "w") f:     k, v in od.items():         f.write("{}=[{}];\n".format(k, " ".join(v)))) 

output:

a1=[{[2,1,2]} {[4,2,1,2,3]}]; a2=[{[3,3,2,1]} {[4,4,2,2]} {[2,2,1,1,1]}]; 

which desired output semicolons removed each sub array, elements grouped , semicolon added end of group keep data valid in matlab file.

the collections.ordereddict keep order original file using normal dict have no order.

a safer approach when updating file write temp file replace original file updated using namedtemporaryfile , shutil.move:

from collections import ordereddict  od = ordereddict() tempfile import namedtemporaryfile shutil import move  open("infile") f, namedtemporaryfile(dir=".", delete=false) temp:     line in f:         name, data = line.split("=")         od.setdefault(name, []).append(data.rstrip("\n;"))     k, v in od.items():         temp.write("{}=[{}];\n".format(k, " ".join(v))) move(temp.name, "infile") 

if code errored in loop or comp crashed during write, original file preserved.