读取文本文件并解释数据

Question

I have to write a program that reads in a text file called "terms.txt" and then sorts the file and prints it with the reference first followed by the page numbers. this is what the file looks like given:

3:degree
54:connected
93:adjacent
54:vertex
19:edge
64:neighbor
72:path
55:shortest path
127:tree
99:spanning tree
19:path
28:connected
3:degree
55:graph
64:adjacent
44:breadth first search
77:neighbor
55:degree
55:depth first search
19:degree
27:neighbor
16:Spanning Tree

and this is what it should like like after being run through the program:

adjacent, 64, 93
breadth first search, 44
connected, 28, 54
degree, 3, 19, 55
depth first search, 55
edge, 19
graph, 55
neighbor, 27, 64, 77
path, 19, 72
shortest path, 55
spanning tree, 16, 99
tree, 127
vertex, 54

Right now, this is what i have and it's just printing a list of the page numbers and a list of the references... I'm not sure where to go from here. Anything will help!

def bookIndex2():
    indexList = []
    pageNum = []
    file = open('terms.txt', 'r')
    for line in file:
        pageNumber, reference = line.split(':')  
        pageNum.append(pageNumber)
        indexList.append(reference)
    indexList.sort()
    print(pageNum)
    print(indexList)

Answer 1

You basically need to use a dictionary that maps the references to a list of page numbers. As you iterate over the file, add the page number to the list for that reference. Once you have processed the whole file, sort and print the dictionary's items. I recommend using collections.defaultdict instead of the standard dictionary as this is quite good a building up a dictionary of lists.

from collections import defaultdict

index = defaultdict(list)
with open('terms.txt') as f:
    for line in f:
        page, reference = line.strip().lower().split(':')
        index[reference].append(int(page))

for reference, pages in sorted(index.items()):
    print "{}, {}".format(reference, ', '.join(str(i) for i in sorted(pages)))

Answer 2

Your result looks like the contents of a dictionary, where the keys are terms and the values are lists of page numbers. The idea would be: for each line of input, add that page number to the list for that term (creating the entry/list if needed). One the dictionary is filled up, just go through the keys in order to produce the desired output.

Answer 3

This might help.

from collections import defaultdict

def bookIndex2():
    file = open('terms.txt', 'r')
    occurance_dict = defaultdict(list)
    for line in file:
        pageNumber, reference = line.split(':')  
        occurance_dict[reference].append(pageNumber)
    for term, occurances in sorted(occurance_dict.items()):
        print [term]+[occurances]

Answer 4

It's very difficult homework...

from collections import defaultdict
def bookIndex2():
    file = open('terms.txt', 'r')
    d = defaultdict(set)
    for line in file:
        num, name = line.strip().split(":")
        d[name.lower()].add(num)
    print "\n".join(map(", ".join, [[name] + sorted(num, key=int) for name, num  in  sorted(d.items())]))

output:

adjacent, 64, 93
breadth first search, 44
connected, 28, 54
degree, 3, 19, 55
depth first search, 55
edge, 19
graph, 55
neighbor, 27, 64, 77
path, 19, 72
shortest path, 55
spanning tree, 16, 99
tree, 127
vertex, 54

Answer 5

If you're looking for something a bit more simple/easier to understand, this might help :)

def bookIndex2():
    appendix = {}

    file = open('terms.txt', 'r')
    for line in file:
        pageNumber, reference = line.split(':')
        reference = reference.rstrip()       "removes \n characters"

        if reference in appendix:
            appendix[reference]=appendix[reference]+', '+pageNumber
        else:
            appendix.update({reference : pageNumber})

    print appendix

The above code stores references as keys in the dictionary. If a reference already exists, then the page number is just appended to the existing reference with a comma.