Question

我正在计算参考和假设的价值。我使用了这段代码，但是我不知道为什么“ wer”没有出现。你能帮我吗？

# -*- coding: UTF-8 -*-

def wer(ref, hyp ,debug=False):
    r = ref.split()
    h = hyp.split()
    #costs will holds the costs, like in the Levenshtein distance algorithm
    costs = [[0 for inner in range(len(h)+1)] for outer in range(len(r)+1)]
    # backtrace will hold the operations we've done.
    # so we could later backtrace, like the WER algorithm requires us to.
    backtrace = [[0 for inner in range(len(h)+1)] for outer in range(len(r)+1)]

    OP_OK = 0
    OP_SUB = 1
    OP_INS = 2
    OP_DEL = 3

    DEL_PENALTY=1 # Tact
    INS_PENALTY=1 # Tact
    SUB_PENALTY=1 # Tact
    # First column represents the case where we achieve zero
    # hypothesis words by deleting all reference words.
    for i in range(1, len(r)+1):
        costs[i][0] = DEL_PENALTY*i
        backtrace[i][0] = OP_DEL

    # First row represents the case where we achieve the hypothesis
    # by inserting all hypothesis words into a zero-length reference.
    for j in range(1, len(h) + 1):
        costs[0][j] = INS_PENALTY * j
        backtrace[0][j] = OP_INS

    # computation
    for i in range(1, len(r)+1):
        for j in range(1, len(h)+1):
            if r[i-1] == h[j-1]:
                costs[i][j] = costs[i-1][j-1]
                backtrace[i][j] = OP_OK
            else:
                substitutionCost = costs[i-1][j-1] + SUB_PENALTY # penalty is always 1
                insertionCost    = costs[i][j-1] + INS_PENALTY   # penalty is always 1
                deletionCost     = costs[i-1][j] + DEL_PENALTY   # penalty is always 1

                costs[i][j] = min(substitutionCost, insertionCost, deletionCost)
                if costs[i][j] == substitutionCost:
                    backtrace[i][j] = OP_SUB
                elif costs[i][j] == insertionCost:
                    backtrace[i][j] = OP_INS
                else:
                    backtrace[i][j] = OP_DEL

    # back trace though the best route:
    i = len(r)
    j = len(h)
    numSub = 0
    numDel = 0
    numIns = 0
    numCor = 0
    if debug:
        print("OP\tREF\tHYP")
        lines = []
    while i > 0 or j > 0:
        if backtrace[i][j] == OP_OK:
            numCor += 1
            i-=1
            j-=1
            if debug:
                lines.append("OK\t" + r[i]+"\t"+h[j])
        elif backtrace[i][j] == OP_SUB:
            numSub +=1
            i-=1
            j-=1
            if debug:
                lines.append("SUB\t" + r[i]+"\t"+h[j])
        elif backtrace[i][j] == OP_INS:
            numIns += 1
            j-=1
            if debug:
                lines.append("INS\t" + "****" + "\t" + h[j])
        elif backtrace[i][j] == OP_DEL:
            numDel += 1
            i-=1
            if debug:
                lines.append("DEL\t" + r[i]+"\t"+"****")
    if debug:
        lines = reversed(lines)
        for line in lines:
            print(line)
        print("Ncor " + str(numCor))
        print("Nsub " + str(numSub))
        print("Ndel " + str(numDel))
        print("Nins " + str(numIns))
    return (numSub + numDel + numIns) / (float) (len(r))
    wer_result = round( (numSub + numDel + numIns) / (float) (len(r)), 3)
    return {'WER':wer_result, 'Cor':numCor, 'Sub':numSub, 'Ins':numIns, 'Del':numDel}

ref= "Ja also bei uns ist dann auch ein Anliegen"

hyp= "Also, bei uns ist dann auch ein Anliegen"

wer(ref, hyp, debug=True)

该脚本有效，但不显示wer吗？你能帮我吗？

结果显示

OP      REF     HYP
DEL     Ja      ****
SUB     also    Also,
OK      bei     bei
OK      uns     uns
OK      ist     ist
OK      dann    dann
OK      auch    auch
OK      ein     ein
OK      Anliegen        Anliegen
Ncor 7
Nsub 1
Ndel 1
Nins 0

我真的不知道为什么wer_result不会出现在终端上，您能帮我解决一下吗？

Answer 1

首先，在return和print之间有一个difference。就您的示例而言，最大的不同是print的副作用是在控制台上显示其参数，而return没有。

第二，您的函数中有两个return调用。每当函数到达代码中的第一个return时，函数都会终止。因此，以下两行将永远不会执行：

wer_result = round( (numSub + numDel + numIns) / (float) (len(r)), 3)
return {'WER':wer_result, 'Cor':numCor, 'Sub':numSub, 'Ins':numIns, 'Del':numDel}

您似乎想要做的就是完全删除第一个return语句，然后将第二个return更改为print()。您是否真的要返回该值取决于您。

功能不显示/返回“单词错误率”？

1 个答案: