我的目标是计算单词数量。当我运行我的代码时，我想：
当我第一次运行代码时，不在文件中写入任何内容，但我在屏幕上看到了结果。该文件为空。只有当我第二次运行代码时，才会看到内容被记录到文件中。
为什么会这样？
#read in the file
fileToRead = open('../folder/strings.txt')
fileToWrite = open('../folder/count.txt', 'w')
d = {}
#iterate over every line in the file
for line in fileToRead:
listOfWords = line.split()
#iterate over every word in the list
for word in listOfWords:
if word not in d:
d[word] = 1
else:
d[word] = d.get(word) + 1
#sort the keys
listF = sorted(d)
#iterate over sorted keys and write them in the file with appropriate value
for word in listF:
string = "{:<18}\t\t\t{}\n".format(word, d.get(word))
print string
fileToWrite.write(string)
答案 0 :(得分：0)
情侣改变，它认为每次打开（'count.txt'，'a'）时你的意思是'a'（附加到文件）而不是'w'覆盖文件。还请尝试使用with语句来读取和写入文件，因为它会在读/写完成后自动关闭文件描述符。
DELIMITER $$
DROP PROCEDURE IF EXISTS sp_AddProduct$$
create procedure sp_AddProduct (
IN PostDate datetime,
IN PostParent int,
IN SKU varchar(10),
IN Weight int,
IN Price Decimal(5,2),
IN Size varchar(10),
IN GUID varchar(250),
IN MenuOrder int
)
BEGIN
DECLARE PostID int;
INSERT INTO wp_posts (
post_author,
post_date,
post_date_gmt,
post_content,
post_title,
post_excerpt,
post_status,
comment_status,
ping_status,
post_password,
post_name,
to_ping,
pinged,
post_modified,
post_modified_gmt,
post_content_filtered,
post_parent,
guid,
menu_order,
post_type,
post_mime_type,
comment_count
)
VALUES (
'1',
PostDate,
PostDate,
'',
'',
'',
'publish',
'open',
'open',
'',
'',
'',
'',
PostDate,
PostDate,
'',
PostParent,
GUID,
MenuOrder,
'product_variation',
'',
0
);/*$$*/
/* Set the PostID = the PostID generated from the above insert*/
-- DECLARE PostID int$$
set PostID = LAST_INSERT_ID();/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_sku',SKU);/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_thumbnail_id',0);/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_virtual','no');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_downloadable','no');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_weight',Weight);/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_length','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_width','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_height','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_manage_stock','no');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_stock_status','instock');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_regular_price',Price);/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_sale_price','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_sale_price_dates_from','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_sale_price_dates_to','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_price',Price);/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_download_limit','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_download_expiry','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_downloadable_files','');/*$$*/
INSERT INTO wp_postmeta(post_id, meta_key, meta_value) VALUES (PostID,'_attribute_pa_size',Size);/*$$*/
END$$
DELIMITER ;
答案 1 :(得分：0)
执行file.write(some_data)时，它会将数据写入缓冲区，但不进入文件。它只会在您执行file.close()时将文件保存到磁盘。
f = open('some_temp_file.txt', 'w')
f.write("booga boo!")
# nothing written yet to disk
f.close()
# flushes the buffer and writes to disk
更好的方法是将路径存储在变量中，而不是文件对象中。然后您可以根据需要打开文件（并再次关闭它）。
read_path = '../folder/strings.txt'
write_path = '../folder/count.txt'
这也允许您使用with关键字，它可以更优雅地处理文件的打开和关闭。
read_path = '../folder/strings.txt'
write_path = '../folder/count.txt'
d = dict()
with open(read_path) as inf:
for line in inf:
for word in line.split()
d[word] = d.get(word, 0) + 1
# remember dict.get's default value! Saves a conditional
# since we've left the block, `inf` is closed by here
sorted_words = sorted(d)
with open(write_path, 'w') as outf:
for word in sorted_words:
s = "{:<18}\t\t\t{}\n".format(word, d.get(word))
# don't shadow the stdlib `string` module
# also: why are you using both fixed width AND tab-delimiters in the same line?
print(s) # not sure why you're doing this, but okay...
outf.write(s)
# since we leave the block, the file closes automagically.
那就是说，你可以采取一些措施使这个更好。首先：计算容器中有多少东西是collections.Counter的作业。
In [1]: from collections import Counter
In [2]: Counter('abc')
Out[2]: Counter({'a': 1, 'b': 1, 'c': 1})
和Counter可以与预期的行为一起添加
In [3]: Counter('abc') + Counter('cde')
Out[3]: Counter({'c': 2, 'a': 1, 'b': 1, 'd': 1, 'e': 1})
并按照您使用键
对字典进行排序的方式进行排序In [4]: sorted((Counter('abc') + Counter('cde')).items(), key=lambda kv: kv[0])
Out[4]: [('a', 1), ('b', 1), ('c', 2), ('d', 1), ('e', 1)]
把所有这些放在一起你可以做类似的事情：
from collections import Counter
read_path = '../folder/strings.txt'
write_path = '../folder/count.txt'
with open(read_path) as inf:
results = sum([Counter(line.split()) for line in inf])
with open(write_path, 'w') as outf:
for word, count in sorted(results.items(), key=lambda kv: kv[0]):
s = "{:<18}\t\t\t{}\n".format(word, count)
outf.write(s)
答案 2 :(得分：0)
简约版：
import collections
with open('strings.txt') as f:
d = collections.Counter(s for line in f for s in line.split())
with open('count.txt', 'a') as f:
for word in sorted(d.iterkeys()):
string = "{:<18}\t\t\t{}\n".format(word, d[word])
print string,
f.write(string)