嘿伙计们，我正试图通过运行以下程序来运行我的程序......
from hashtable import *
def word_count( hTable, filename ):
"""
Record the frequency of all words in the named file in the hashtable.
word_count : HashTable String -> HashTable
"""
# Read the words of the text file into the word count table.
fd = open( filename )
for line in fd:
for word in line.split():
# using a regular expression argument to strip(),
# strip out punctuation and convert token to lower-case.
word = word.strip(",.\"\';:-!?").lower()
if contains( hTable, word ):
count = get( hTable, word )
put( hTable, word, count + 1 )
else:
put( hTable, word, 1 )
fd.close() # closing the file is a 'good practice'.
return hTable
def printSummary( theTable ):
"""
printSummary prints a summary of information about the hash table contents.
printSummary : HashTable -> NoneType
"""
# Display the entire table!
print( "Unique words:", theTable.size )
# Find the most common word in the text file.
total = 0
maxWord = ""
maxCount = 0
for key in keys( theTable ):
thisCount = get( theTable, key )
total += thisCount
if thisCount > maxCount:
maxCount = thisCount
maxWord = key
print( "There are " + str( len( keys( theTable ) ) ) + " words." )
print( "Total words:", total )
print( '"' + maxWord + "\" appeared ", str( maxCount ),
" times, more than any other word." )
def printTable( hTable ):
"""
Print the contents of the given hash table.
Each key/value pair is displayed in parentheses, tuple-style.
All pairs appear on a single line.
printTable : HashTable -> NoneType
"""
print( "Word Count Data ---------------" )
lcount = 0
ltext = 0
for key in keys( hTable ):
# print( "(" + key + "," + str( get( hTable, key ) ) + ")", end=" " )
txt = "(" + key + "," + str( get( hTable, key ) ) + ")"
ltext += len( txt )
if ltext > 51:
print( txt )
ltext = 0
else:
print( txt, end=" " )
print()
def main():
capacity = int( input( "Enter capacity (-1 for default): " ) )
if capacity < 0:
hTable = HashTable()
else:
hTable = HashTable( capacity )
filename = input( "Enter filename: " )
wordTable = word_count( hTable, filename )
printSummary( wordTable )
while True:
print( "Commands: k[ey] <word> f[ind] <word> q[uit] ? ", end=" " )
response = input( ":- " ) # the displayed prompt
query = response.split()
if len( response ) == 0 or not response[0] in "fkq":
print( response + " invalid. Please enter a command and a word." )
response = ""
continue
if query[0] == "k":
print( "( " + query[1] + " in text ) is " \
+ str( contains( wordTable, query[1] ) ) + "." )
if query[0] == "f":
if contains( wordTable, query[1] ):
print( query[1] + " appears " \
+ str( get( wordTable, query[1] ) ) + " times." )
else:
print( query[1] + " in not in the text." )
if query[0] == "q":
break
#
answer = input( "Do you want to see the entire table?(y/n) " )
if answer != "y":
return
printTable( wordTable )
# run the main program
main()
该程序使用......
class HashTable( ):
"""
The HashTable data structure contains a collection of values
where each value is located by a hashable key.
No two values may have the same key, but more than one
key may have the same value.
"""
__slots__ = ( "table", "size" )
def mkHashTable(capacity=100):
aHashTable = HashTable()
aHashTable.table = [[] for _ in range(capacity)]
aHashTable.size = 0
return aHashTable
def HashTableToStr(hashtable):
result = ""
for i in range( len( hashtable.table ) ):
if i != None:
result += str( i ) + ": "
result += EntryToStr( hashtable.table[i] ) + "\n"
return result
class _Entry( ):
"""
A class used to hold key/value pairs.
"""
__slots__ = ( "key", "value" )
def EntryToStr(entry):
"""
return the string representation of the entry.
"""
return "(" + str( entry.key ) + ", " + str( entry.value ) + ")"
def mkEntry(key, value):
aEntry = _Entry();
aEntry.key = key;
aEntry.value = value;
return aEntry;
def hash_function( val, n ):
"""
Compute a hash of the val string that is in [0 ... n).
"""
hashcode = hash( val ) % n
# hashcode = 0
# hashcode = len(val) % n
return hashcode
def keys( hTable ):
"""
Return a list of keys in the given hashTable.
"""
result = []
for entry in hTable.table:
if entry != []:
for item in entry:
if item.key not in results:
result.append( entry.key )
return result
def contains( hTable, key ):
"""
Return True iff hTable has an entry with the given key.
"""
index = hash_function( key, len( hTable.table ) )
startIndex = index # We must make sure we don't go in circles.
while hTable.table[ index ] != None and hTable.table[ index ].key != key:
index = ( index + 1 ) % len( hTable.table )
if index == startIndex:
return False
return hTable.table[ index ] != None
def put( hTable, key, value ):
"""
Using the given hash table, set the given key to the
given value. If the key already exists, the given value
will replace the previous one already in the table.
If the table is full, an Exception is raised.
"""
hashCode = hash(key)
loc = hashCode % len(hTable.table)
if hTable.table[loc] == []:
hTable.table[loc] = HashTable._Entry(key, value)
hTable.size += 1
else:
hTable.table[loc].value = value
def get( hTable, key ):
"""
Return the value associated with the given key in
the given hash table.
Precondition: contains(hTable, key)
"""
hashCode = hash(key)
loc = hashCode % len(hTable.table)
for entry in hTable.table[loc]:
if entry.key == key:
return entry.value
我收到以下错误...
Enter capacity (-1 for default): -1
Enter filename: words.txt
Traceback (most recent call last):
File "/Users/sps329/Desktop/word_count.py", line 126, in <module>
main()
File "/Users/sps329/Desktop/word_count.py", line 92, in main
wordTable = word_count( hTable, filename )
File "/Users/sps329/Desktop/word_count.py", line 29, in word_count
if contains( hTable, word ):
File "/Users/sps329/Desktop/hashtable.py", line 83, in contains
index = hash_function( key, len( hTable.table ) )
AttributeError: table
我在程序中的目标是在哈希程序中实现链接并提出更好的哈希函数。
答案 0 :(得分：3)
在HashTable中构建main()实例的代码不正确。您正在调用HashTable构造函数而不是实际将mkHashTable属性放在table实例中的HashTable工厂函数。如果没有初始化table属性，您将获得您描述的异常。
请注意，您的hashtable模块设计非常糟糕。 HashTable类的__init__方法确实应该重新设计，以执行mkHashTable所做的事情。让构造函数返回一个非功能对象是愚蠢的。
它不是唯一糟糕的设计。 hashtable.py中的几乎所有函数都应该是HashTable（或_Entry）类的方法。如果它们以特殊方式命名，其中一些可以得到Python的特殊支持：contains应该是__contains__方法（允许您使用word in table进行测试）和HashTableToStr应该是__str__方法（因此您可以使用print(table)打印）。