Python 字符和字数

Question

我是 python 的初学者，想知道如何使用两个 txt 文件来计算字符以及计算 10 个最常见的字符。以及如何将文件中的所有字符转换为小写并消除除a-z之外的所有字符

这是我尝试过但没有成功的方法：

from string import ascii_lowercase
from collections import Counter

with open ('document1.txt' , 'document2.txt') as f:
    print Counter(letter for line in f
                    for letter in line.lower()
                    if letter in ascii_lowercase)

Answer 1

试试这样：

>>> from collections import Counter
>>> import re
>>> words = re.findall(r'\w+', "{} {}".format(open('your_file1').read().lower(), open('your_file2').read().lower()))
>>> Counter(words).most_common(10)

Answer 2

这是一个简单的例子。您可以调整此代码以满足您的需求

from string import ascii_lowercase
from collections import Counter

with open('file1.txt', 'r') as file1data: #opening an reading file one
    file1 = file1data.read().lower() #convert the entire file contents to lower

with open('file2.txt', 'r') as file2data: #opening an reading file two
    file2 = file2data.read().lower() 

#The contents of both file 1 and 2 are stored in fil1 and file2 variables
#Examples of how to work with one file repeat for two files
file1_list = []
for ch in file1:
    if ch in ascii_lowercase: #makes sure only lowercase alphabet is appended.  All Non alphabet characters are removed
        file1_list.append(ch)
    elif ch in [" ", ".", ",", "'"]: #remove this elif block is you just want the letters
        file1_list.append(ch) #make sure basic punctionation is kept

print "".join(file1_list) #this line is not needed. Just to show what the text looks like now
print Counter(file1_list).most_common(10) #prints the top ten
print Counter(file1_list) #prints the number of characters and how many times they repeat

现在您已经查看了上面的混乱并了解了每一行的作用，这里有一个更简洁的版本，可以满足您的需求。

from string import ascii_lowercase
from collections import Counter

with open('file1.txt', 'r') as file1data: 
    file1 = file1data.read().lower()

with open('file2.txt', 'r') as file2data: 
    file2 = file2data.read().lower() 

file1_list = []
for ch in file1:
    if ch in ascii_lowercase: 
        file1_list.append(ch)

file2_list = []
for ch in file2:
    if ch in ascii_lowercase: 
        file2_list.append(ch)



all_counter = Counter(file1_list + file2_list) 
top_ten_counter = Counter(file1_list + file2_list).most_common(10) 

print sorted(all_counter.items()) 
print sorted(top_ten_counter)

Answer 3

不幸的是，没有办法在不重写文件的情况下插入文件的中间。正如之前的海报所指出的那样，您可以使用 seek 附加到文件或覆盖文件的一部分，但如果您想在开头或中间添加内容，则必须重写它。

这是操作系统的事情，而不是 Python 的事情。在所有语言中都是一样的。

我通常做的是从文件中读取，进行修改并将其写入一个名为 myfile.txt.tmp 或类似文件的新文件。这比将整个文件读入内存要好，因为文件可能太大了。临时文件完成后，我将其重命名为与原始文件相同。

这是一种很好、安全的方法，因为如果文件写入因任何原因崩溃或中止，您仍然拥有未触及的原始文件。

要从多个文件中找到最常见的words，

from collections import Counter
import re
with open(''document1.txt'') as f1, open(''document1.txt'') as f2:
    words = re.findall(r'\w+', f1.read().lower()) + re.findall(r'\w+', f2.read().lower())
    >>>Counter(words).most_common(10)
    "wil give you most 10 common words"

如果你想要最常见的 10 个characters

>>>Counter(f1.read() + f2.read()).most_common(10)