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How do you delete an ActiveRecord object?
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It's destroy and destroy_all methods, like
user.destroy
User.find(15).destroy
User.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)
Alternatively you can use delete and delete_all which won't enforce :before_destroy and :after...
Which $_SERVER variables are safe?
...ttacker can also control and is therefore a source of an attack. This is called a "tainted" variable, and is unsafe.
2 An...
Git: How to return from 'detached HEAD' state
If one would checkout a branch:
4 Answers
4
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Python - Passing a function into another function
I am solving a puzzle using python and depending on which puzzle I am solving I will have to use a special set of rules. How can I pass a function into another function in Python?
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Pure JavaScript Send POST Data Without a Form
Is there a way to send data using the POST method without a form and without refreshing the page using only pure JavaScript (not jQuery $.post() )? Maybe httprequest or something else (just can't find it now)?
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Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
Efficiency of purely functional programming
...ssible asymptotic slowdown that can happen when programming purely functionally as opposed to imperatively (i.e. allowing side-effects)?
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What does [:] mean?
...he type of population. If population is a list, this line will create a shallow copy of the list. For an object of type tuple or a str, it will do nothing (the line will do the same without [:]), and for a (say) NumPy array, it will create a new view to the same data.
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Linq to Sql: Multiple left outer joins
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This may be cleaner (you dont need all the into statements):
var query =
from order in dc.Orders
from vendor
in dc.Vendors
.Where(v => v.Id == order.VendorId)
.DefaultIfEmpty()
from status
in dc.Status
.Where(...
Alias with variable in bash [duplicate]
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I'd create a function for that, rather than alias, and then exported it, like this:
function tail_ls { ls -l "$1" | tail; }
export -f tail_ls
Note -f switch to export: it tells it that you are exporting a function. Put this in your .b...