Question

我正在尝试让python计算文本文件中有多少字母或符号。我的文本文件是'*#%##'但是由于某种原因，当我输入一个符号时，它会计算所有字符而不是输入，所以如果我输入'#'，我得到的输出为5而不是3。 / p>

这是我到目前为止所做的：

Symbol = input("Pick a Symbol ")
freq = 0
with open ("words.txt", "r") as myfile:
    data = myfile.read().replace('\n', '')
    print(data)
    for Symbol in data:
        freq = (freq + 1)
print(freq)

Answer 1

您正在Symbol循环中重新绑定for：

for Symbol in data:

这只是将文件中的每个字符分配给Symbol，然后递增计数。

改为使用str.count()：

with open ("words.txt", "r") as myfile:
    data = myfile.read().replace('\n', '')
    print(data)
    freq = data.count(Symbol)
    print(freq)

或者，如果必须使用循环，则测试每个字符：

with open ("words.txt", "r") as myfile:
    data = myfile.read().replace('\n', '')
    print(data)
    freq = 0
    for char in data:
        if char == Symbol:
            freq = freq + 1
    print(freq)

Answer 2

对于大型输入文件，您可能需要考虑collections.Counter

from collections import Counter

def countsymbols(filename,symbols):
    """Counts the symbols in `filename`.
`symbols` is an iterable of symbols"""
    running_count = Counter()

    with open(filename) as f:
        for line in f:
            running_count += Counter(line.strip())

    return {key:value for key,value in running_count.items() if key in symbols}

symbols = map(str.strip,input("Enter symbols: ").split())
filename = input("Filename: ")

symbolcount = countsymbols(filename,symbols)

在Python中计算文本文件中的特定字母或符号

2 个答案: