[英]Python: how to parse and and add contents to a text file
Hello I have a network in a particular format, ie .gdf
. 您好,我有一个特定格式的网络,即
.gdf
。 However this is a text file in the following format 但是,这是一个以下格式的文本文件
network:
nodedef>name VARCHAR,label VARCHAR
0,' 0 '
1,' 1 '
2,' 2 '
edgedef>node1 VARCHAR,node2 VARCHAR,weight DOUBLE
0,1,0.2
0,2,0.2
0,3,0.2
0,4,0.333333
where the first part refers to nodes and the second part to edges. 第一部分引用节点,第二部分引用边缘。
I want to add feature to read the file and add a feature to the nodes and return the following: 我想添加功能来读取文件并向节点添加功能并返回以下内容:
network:
nodedef>name VARCHAR,label VARCHAR, att1 VARCHAR
0,' 0 ', 'Paul'
1,' 1 ', 'Jack'
2,' 2 ', 'John'
edgedef>node1 VARCHAR,node2 VARCHAR,weight DOUBLE
0,1,0.2
0,2,0.2
0,3,0.2
0,4,0.333333
Here is some code that does the first half of what you asked for. 以下是一些代码,用于执行您要求的上半部分。 It will parse the .GDF file and make the information available to you.
它将解析.GDF文件并使您可以获得信息。 Adding attributes and writing them is left as an exercise for the reader.
添加属性并编写它们留给读者练习。
import ast
import collections
import re
def main():
parser = GDFParser()
with open('network.gdf') as file:
parser.read(file)
print(*parser.data, sep='\n')
def pivot(iterable):
columns = []
for row in iterable:
columns.extend([] for _ in range(len(row) - len(columns)))
for column, cell in zip(columns, row):
column.append(cell)
return columns
class GDFParser:
HEADER = re.compile('\w+:')
DEF = re.compile('\w+>\w+ (?:DOUBLE|VARCHAR)(?:,\w+ (?:DOUBLE|VARCHAR))*')
CAST = dict(DOUBLE=float, VARCHAR=str)
def __init__(self):
self.__header = None
self.__type = []
self.__data = []
@property
def header(self):
return self.__header
@property
def data(self):
return tuple(self.__data)
def read(self, file):
for line in file:
self.__read_line(line.strip())
def __read_line(self, line):
if self.HEADER.fullmatch(line):
self.__process_header(line)
elif self.DEF.fullmatch(line):
self.__process_def(line)
else:
self.__process_data(line)
def __process_header(self, line):
if self.header:
raise ValueError('header was previously set')
self.__header = line[:-1]
def __process_def(self, line):
name, fields = line.split('>')
columns, casts = pivot(field.split() for field in fields.split(','))
self.__type.append((collections.namedtuple(name, columns),
tuple(map(self.CAST.__getitem__, casts))))
def __process_data(self, line):
if not self.__type:
raise ValueError('a definition must come before its data')
kind, casts = self.__type[-1]
self.__data.append(kind(*(cast(item) for cast, item in
zip(casts, ast.literal_eval(line)))))
if __name__ == '__main__':
main()
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