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Saving an Object (Data persistence)
...40)
pickle.dump(company1, output, pickle.HIGHEST_PROTOCOL)
company2 = Company('spam', 42)
pickle.dump(company2, output, pickle.HIGHEST_PROTOCOL)
del company1
del company2
with open('company_data.pkl', 'rb') as input:
company1 = pickle.load(input)
print(company1.name) # -> ...
What's the safest way to iterate through the keys of a Perl hash?
...eys with doubled values works fine using keys():
%h = (a => 1, b => 2);
foreach my $k (keys %h)
{
$h{uc $k} = $h{$k} * 2;
}
producing the expected resulting hash:
(a => 1, A => 2, b => 2, B => 4)
But using each() to do the same thing:
%h = (a => 1, b => 2);
keys %h...
Reading an Excel file in python using pandas
...
229
Close: first you call ExcelFile, but then you call the .parse method and pass it the sheet nam...
Show pending migrations in rails
...
261
rake db:migrate:status (Rails 3 to 5) or rails db:migrate:status (Rails 5) will accomplish thi...
Maven 3 warnings about build.plugins.plugin.version
...lt;artifactId>maven-compiler-plugin</artifactId>
<version>2.3.2</version>
The warning should be resolved.
Regarding this:
'build.plugins.plugin.version' for
org.apache.maven.plugins:maven-compiler-plugin is missing
Many people have mentioned why the issue is happeni...
How can I suppress all output from a command using Bash?
...rk in all shells):
scriptname &>/dev/null
scriptname >/dev/null 2>&1
scriptname >/dev/null 2>/dev/null
And, if you want to record the messages, but not see them, replace /dev/null with an actual file, such as:
scriptname &>scriptname.out
For completeness, under Wi...
How do you use the ? : (conditional) operator in JavaScript?
...userType = "Minor";
} else {
userType = "Adult";
}
if (userIsYoungerThan21) {
serveDrink("Grape Juice");
} else {
serveDrink("Wine");
}
This can be shortened with the ?: like so:
var userType = userIsYoungerThan18 ? "Minor" : "Adult";
serveDrink(userIsYoungerThan21 ? "Grape Juice" : "Wine...
Count number of records returned by group by
... COUNT(*) OVER () AS TotalRecords
from temptable
group by column_1, column_2, column_3, column_4
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How to reshape data from long to wide format
...
268
Using reshape function:
reshape(dat1, idvar = "name", timevar = "numbers", direction = "wide"...