Question

我的代码应该一直将恐龙骨骼显示在.txt文件中，但是我的代码指出所有骨骼都显示0次。

print('Bones found:')
f=open('bones.txt')
bones = {line.replace('\n', ''): 0 for line in f}
for bone in f:
  if bone in bones:
    bones[bone]=bones[bone]+1

for y in bones:
  print(y+':'+str(bones[y]))

bones.txt文件为：

Ankylosaurus
Pachycephalosaurus
Ankylosaurus
Tyrannosaurus Rex
Ankylosaurus
Struthiomimus
Struthiomimus

它说：

Bones found:
Ankylosaurus:0
Pachycephalosaurus:0
Tyrannosaurus Rex:0
Struthiomimus:0

但应该说：

Bones found:
Ankylosaurus: 3
Pachycephalosaurus: 1
Tyrannosaurus Rex: 1
Struthiomimus: 2

Answer 1

您只能使用一个迭代器（通过使用open(file.txt)获得一次。以下代码应适用于您的情况。此代码使用了Counter，它包含在标准python中库，用于计数字符串的出现。

通过使用计数器

# import the Counter so it can be used
from collections import Counter
# open the text file in read mode, by using this construct, 
# the lock will be released after the with-block to ensure 
# resources are freed correctly
with open("bones.txt") as file:
    # for every line in the file; remove the \n and insert it into the counter
    counts = Counter(line.strip() for line in file)

# print every key in the counter
for dinosaur in counts:
    print("{}: {}".format(dinosaur, counts[dinosaur]))

使用字典

此代码不使用计数器，但操作完全相同。

# open the text file in read mode, by using this construct, 
# the lock will be released after the with-block to ensure 
# resources are freed correctly
with open("bones.txt") as file:
    # create a dictionary to store the counts
    counts = dict()
    # iterate over every line in the file
    for line in file:
        # remove the \n from the line
        stripped = line.strip()

        if stripped in counts:
            # key already exists -> increment it
            counts[stripped] += 1
        else:
            # key doesn't exist -> add it
            counts[stripped] = 1

# print every key in the counts dictionary
for dinosaur in counts:
    print("{}: {}".format(dinosaur, counts[dinosaur]))

输出

Pachycephalosaurus: 1
Struthiomimus: 2
Ankylosaurus: 3
Tyrannosaurus Rex: 1

计算文件中字符串的出现

1 个答案: