Question

编写程序以检查用户输入的单词是否在预先存在的集合中;无论我输入什么单词，程序都会返回＆＃34; False＆＃34; （即使它是我知道的一个词在集合中）。代码如下：

name = input("which file would you like to open?  ")
s=input("word?  ")

F = open(name, "r")
words = set()
words.add(F)

def contains(s,words):
    if s in words:
        print("true")
    else:
        print("false")
contains(s,words)

Answer 1

假设文件中每行有一个单词，例如

asd
asdf

您可以使用此功能，将每行添加到words：

name = input("which file would you like to open?  ")
s = input("word?  ")

F = open(name, "r")
words = set()
for line in F:  # add every line to words (assuming one word per line)
    words.add(line.strip())

def contains(s, words):
    if s in words:
        print("true")
    else:
        print("false")

contains(s, words)

打印输出：

which file would you like to open?  file.txt
word?  asd
true

编辑：实际任务的缩短方式：

name = input("which file would you like to open?  ")
s = input("word?  ")

F = open(name, "r")
print("true") if s in F.read() else print("false")

Answer 2

假设您的文件如下所示：

banana
apple
apple
orange

让我们创建该文件：

with open("test.txt","w") as f:
    f.write("banana\napple\napple\norange")

现在让我们运行示例代码：

s= input("word?  ")

words = set()

# Using with we don't need to close the file
with open("test.txt") as f:
    # here is the difference from your code
    for item in f.read().split("\n"):
        words.add(item)

def contains(s,words):
    for word in words:
        if s in word:
            print("true")
            break
    else:
        print("false")

contains(s,words)

打字：

apple returns "true"

ap returns "true"

oeoe returns "false"

Answer 3

正确的方法是使用生成器：

name = input("which file would you like to open?  ")
word_to_look_for=input("word?  ")

def check(word_to_look_for, word_from_file):
    return word_to_look_for == word_from_file

with open(name, "r") as file:
    # The code inside the parentheses () returns a generator object
    word_exists = (check(word_to_look_for, word_from_file.rstrip("\n")) for word_from_file in file.readlines())  

# This will return true if either one of the "check" function results is True 
print(any(word_exists))

Answer 4

这里有一些事情，我不确定你是否完全清楚：

首先，F是一个文件。我猜这里你的意图是你要检查一个单词是否在一个单词文件中（如字典）。要做到这一点，你需要做这样的事情：

filename = "somefilename.txt"
words = set()
# open the file
file = open(filename, "r")
# read the lines into an array
lines = file.readlines()

for line in lines:
    words.add(line)

testWord = input("word?  ")

第二个问题是你正在使用一个函数，但是你将参数误认为是你在主流中声明的相同变量。例如

# this is a verbose way of doing this   
words = set()
testWord = input()
def isWordInSet(word, words):
    # words here is not the same as the words
    # outside the function
    if word in words:
        print("True")
    else:
        print("False")

isWordInSet(testWord, words)

Answer 5

首先，最好使用

打开文件

with open(filepath, 'r') as input_file:

你可以在这里读到这个 https://docs.python.org/3/tutorial/inputoutput.html

此外，您尝试将文件添加到集中，但您需要添加单词。所以这是有效的（和更多的pythonic）代码：

import os

def load_data(filepath):
    if not os.path.exists(filepath):
        return None
    with open(filepath, 'r') as input_file:
        text = input_file.read()
    return text

if __name__ == '__main__':
    filepath = input("Which file would you like to open?")
    word=input("What we want to find?")
    text = load_data(filepath)
    if not text:
        print("File is empty or not exists!")
        raise SystemExit
    words = set(text.split())
    print(word in words)

检查项目是否在Python中的集合中？

5 个答案: