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Difference between del, remove and pop on lists
...ement from a list:
remove removes the first matching value, not a specific index:
>>> a = [0, 2, 3, 2]
>>> a.remove(2)
>>> a
[0, 3, 2]
del removes the item at a specific index:
>>> a = [9, 8, 7, 6]
>>> del a[1]
>>> a
[9, 7, 6]
and pop removes t...
“where 1=1” statement [duplicate]
...
It's usually when folks build up SQL statements.
When you add and value = "Toyota" you don't have to worry about whether there is a condition before or just WHERE. The optimiser should ignore it
No magic, just practical
Example ...
How to override and extend basic Django admin templates?
How do I override an admin template (e.g. admin/index.html) while at the same time extending it (see https://docs.djangoproject.com/en/dev/ref/contrib/admin/#overriding-vs-replacing-an-admin-template )?
...
How do I print out the contents of an object in Rails for easy debugging?
...onView::Helpers::DebugHelper
#app/view/controllers/post_controller.rb
def index
@posts = Post.all
end
#app/view/posts/index.html.erb
<%= debug(@posts) %>
#start your server
rails -s
results (in browser)
- !ruby/object:Post
raw_attributes:
id: 2
title: My Second Post
body: ...
Setting element of array from Twig
...
I ran into this problem but was trying to create integer indexes instead of associative index like 'element'.
You need to protect your index key with () using the merge filter as well:
{% set arr = arr|merge({ (loop.index0): 'value'}) %}
You can now add custom index key like (...
Add a prefix to all Flask routes
... prefix:
app.config["APPLICATION_ROOT"] = "/abc/123"
@app.route("/")
def index():
return "The URL for this page is {}".format(url_for("index"))
# Will return "The URL for this page is /abc/123/"
Setting the APPLICATION_ROOT config value simply limit Flask's session cookie to that URL prefix...
MySQL Cannot drop index needed in a foreign key constraint
...NIQUE field to encompass that new column. I'm trying to remove the current index but keep getting the error MySQL Cannot drop index needed in a foreign key constraint
...
Reverse a string in Python
...hile loop:
def reverse_a_string_slowly(a_string):
new_string = ''
index = len(a_string)
while index:
index -= 1 # index = index - 1
new_string += a_string[index] # new_string = new_string + character
return new_string
This is theoretically bad be...
Selecting a row of pandas series/dataframe by integer index
...YRY, see the new docs in 0.11
http://pandas.pydata.org/pandas-docs/stable/indexing.html
Here we have new operators, .iloc to explicity support only integer indexing, and .loc to explicity support only label indexing
e.g. imagine this scenario
In [1]: df = pd.DataFrame(np.random.rand(5,2),index=r...
How to get the sizes of the tables of a MySQL database?
...les first):
SELECT
table_name AS `Table`,
round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB`
FROM information_schema.TABLES
WHERE table_schema = "$DB_NAME"
AND table_name = "$TABLE_NAME";
or this query to list the size of every table in every database, largest fir...