计算出现在word文件中的后缀

Question

I have got this python program which reads through a wordlist file and checks for the suffixes ending which are given in another file using endswith() method. the suffixes to check for is saved into the list: suffixList[] The count is being taken using suffixCount[]

The following is my code:

fd = open(filename, 'r')
print 'Suffixes: '
x = len(suffixList)
for line in fd:
   for wordp in range(0,x):
        if word.endswith(suffixList[wordp]):
           suffixCount[wordp] = suffixCount[wordp]+1
for output in range(0,x):
     print  "%-6s %10i"%(prefixList[output], prefixCount[output])

fd.close()

The output is this :

Suffixes: 
able            0
ible            0
ation           0

the program is unable to reach this loop :

if word.endswith(suffixList[wordp]):

Answer 1

You need to strip the newline:

word = ln.rstrip().lower()

The words are coming from a file so each line ends with a newline character. You are then trying to use endswith which always fails as none of your suffixes end with a newline.

I would also change the function to return the values you want:

def store_roots(start, end):
    with open("rootsPrefixesSuffixes.txt") as fs:
        lst = [line.split()[0] for line in map(str.strip, fs)
                       if '#' not in line and line]
        return lst, dict.fromkeys(lst[start:end], 0)

lst, sfx_dict = store_roots(22, 30) # List, SuffixList

Then slice from the end and see if the substring is in the dict:

with open('longWordList.txt') as fd:
    print('Suffixes: ')
    mx, mn = max(sfx_dict, key=len), min(sfx_dict, key=len)
    for ln in map(str.rstrip, fd):
        suf = ln[-mx:]
        for i in range(mx-1, mn-1, -1):
            if suf in sfx_dict:
                sfx_dict[suf] += 1
            suf = suf[-i:]
    for k,v in sfx_dict:
        print("Suffix = {} Count =  {}".format(k,v))

Slicing the end of the string incrementally should be faster than checking every string especially if you have numerous suffixes that are the same length. At most it does mx - mn iterations, so if you had 20 four character suffixes you would only need to check the dict once, only one n length substring can be matched at a time so we would kill n length substrings at the one time with a single slice and lookup.

Answer 2

You could use a Counter to count the occurrences of suffix:

from collections import Counter

with open("rootsPrefixesSuffixes.txt") as fp:
    List = [line.strip() for line in fp if line and '#' not in line]
suffixes = List[22:30]  # ?

with open('longWordList.txt') as fp:
    c = Counter(s for word in fp for s in suffixes if word.rstrip().lower().endswith(s))
print(c)

Note: add .split()[0] if there are more than one words per line you want to ignore, otherwise this is unnecessary.