as mean renaming the file? does it have any special meaning here?
as mean renaming the file? does it have any special meaning here?
print out their types and find that the types are inconsistent.
In [5]: import json
In [6]: num = [1,2,3,4,5,6,7]
In [7]: file_1 = 'first.json'
In [8]: with open(file_1,'w') as joe:
...: print(type(joe))
...: json.dump(num, joe)
...:
<class '_io.TextIOWrapper'>In [14]: import json
In [15]: num = [1,2,3,4,5,6,7]
In [16]: file_1 = 'first.json'
In [17]: with open(file_1, 'w'):
...: print(type(file_1))
...: json.dump(num, file_1)
...:
...:
...:
<class 'str'>
AttributeError: 'str' object has no attribute 'write' the second section of code
uses the open method to open the file, but still uses the direct string object file_1, which is equivalent to no open.
is equivalent to the following code:
import json
file_1 = 'first.json'
json.dump(num, file_1)and the string itself is not written to this method, so the error is: AttributeError: 'str' object has no attribute' write'
if you don't want with, you can assign the open object to f = open (file_1,'w')
. as is not renaming the original file.
as represents the opened file handle. For example, f = open (file_1,'w') , the one after as is equivalent to this f variable. With is used because with is a context manager that automatically closes files. There is no need to call f.close ().
with as is context manager , implemented using Python's magic method .
refer to python/sub-2" rel=" nofollow noreferrer "> context Manager -python/28" rel= "nofollow noreferrer" > Magic method
Previous: Yii2 php recycle mysql transactions
Next: Electron-vue, does not respond to net socket connect in click events, but it works in created. Why?
dict1 = { "system.cpu.user.pct": { "value": 12.83 }, "system.load.1": { "value": 0.33 } } dict2 = { "system": { "...
description: a regular match is given to the content of an input box, and the matching content is the product activation code. looks like this: "0C31-0B81-BB32-3094-0C31-0B81-BB32-3094 " Code: $( -sharplicenseCode ).keyup(function () { le...
for example, the known two-dimensional list [[aformab], [dpene], [f]] requires an element from each sublist to be added and lists all the combinations. The output of this question is adf,aef,bdf,bef,cdf,cef. There are many such lists, and the number of s...
I want the program to randomly issue five cards with different colors and numbers (it doesn t matter if there are occasional cards with the same number), but I find that five cards are always the same. import random suites = [ "Hearts ", "Diamonds ...
this problem works fine after I add code to the first line, but do I have to pay attention to this every time? Python novice asks ...
{% csrf_token%}, is added to the form form of html in the template. MIDDLEWARE = [ django.middleware.security.SecurityMiddleware , django.contrib.sessions.middleware.SessionMiddleware , django.middleware.common.CommonMiddleware , ...
when we use the ansible tool, the default is to use ssh for remote control. you need to generate key pairs in a way similar to ssh-keygen-t rsa , and then use the ssh-copy-id command to distribute the public key file to a remote host and enter the pas...
python replaces the content in front of the vertical bar symbol in the title, but it has been unsuccessful, for example: Chen Ning column (Chinese football fight to correct the name of Wales Uruguay for the championship, replace Chen Ning column for oth...
the article on Wechat s official account crawled through python at the backend found that the video in the article could not be played, and the video was nested in iframe, as shown in <iframe class="video_iframe" data-vidtype="2"...
as in the title, write a simple function test to generate a soup object from the URL using Python requests and BeautifulSoup, (see the example below). If you call this function directly in the main thread, everything will be fine, but if you call this f...
blog s article like function, like once + 1, use session to record the current user problem point is: if you like article 1, article 2 will indicate that it has been supported. The reason is to judge that session how to realize that articles cannot b...
1. Condition: according to whether the alias in the two lines intersect, and if so, Then merge separated by-sharp sign, where: alias 2 in alias separated by-sharp sign, data name alias 0 potato potato-sharp egg-sharp potato-sharp potato 1 potato p...
Baidu said that there is a problem with the verification method in the file var lib pgsql 9.5 data pg_hba.conf, but the reason for changing the verification method is to use the command psql-U postgres-d mydjango-p 5432-h 127.0.0.1 to log in directl...
I ve been looking for it for a long time, but I can t find it. 1. After the direct upload of web is completed, the server cannot know whether the file was uploaded successfully, who uploaded it, and the information of the file 2. Using web to dire...
currently I have a piece of code that spends most of its time on the above two sentences of data filtering in dataframe. temp_df = df [df [ "data_date "] .isin (date_list)] temp = temp_df [rule [2]] [temp_df [ "data_date "] = = d] at present, it tak...
< H2 > 1. Question: < H2 > like the title, how does the chart displayed by matplotlib.pyplot.show () in pycharm pop up to sciview,? < H2 > 2. Code: < H2 > import matplotlib.pyplot as plt import matplotlib.animation as animation from matplotlib impo...
I need to install both python 2.6 and python 3.6 on my machine. Based on my query, I found that I could use pyenv to do this things, but according to an article I read, python 2 series didn t come with package management tools until python 2.7.9. The...
The question is written on the title, is there any way to be spaced by BAN, when it is applied too fast in crawlers? Or is it that there is no interval in this kind of concurrency? ...
Open a chrome browser using selenium, and open a Baidu web page. Using the send_keys () method to fill in the content in the search box, there are the following problems -sharpcoding:utf-8 from selenium import webdriver from selenium.webdriver.chrom...
the newly installed win7 system, Ann python is, the installation package setup comes out of this, which I have encountered before. I forgot how to solve it. ...