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What is the difference between join and merge in Pandas?
...ys use join on indices:
import pandas as pd
left = pd.DataFrame({'key': ['foo', 'bar'], 'val': [1, 2]}).set_index('key')
right = pd.DataFrame({'key': ['foo', 'bar'], 'val': [4, 5]}).set_index('key')
left.join(right, lsuffix='_l', rsuffix='_r')
val_l val_r
key
foo 1 4
ba...
Concatenate two slices in Go
...}, []int{3,4}...)
This is just like any other variadic function.
func foo(is ...int) {
for i := 0; i < len(is); i++ {
fmt.Println(is[i])
}
}
func main() {
foo([]int{9,8,7,6,5}...)
}
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TypeError: 'NoneType' object is not iterable in Python
...erable
Python methods return NoneType if they don't return a value:
def foo():
print("k")
a, b = foo() #TypeError: 'NoneType' object is not iterable
You need to check your looping constructs for NoneType like this:
a = None
print(a is None) #prints True
print(a is not No...
Singleton pattern in nodejs - is it needed?
... are loaded. This means
(among other things) that every call to require('foo') will get
exactly the same object returned, if it would resolve to the same
file.
Multiple calls to require('foo') may not cause the module code to be
executed multiple times. This is an important feature. Wit...
What are the differences between Abstract Factory and Factory design patterns?
......
What they're saying is that there is an object A, who wants to make a Foo object. Instead of making the Foo object itself (e.g., with a factory method), it's going to get a different object (the abstract factory) to create the Foo object.
Code Examples
To show you the difference, here is a fact...
What is a “callable”?
...
Called when the instance is ''called'' as a function
Example
class Foo:
def __call__(self):
print 'called'
foo_instance = Foo()
foo_instance() #this is calling the __call__ method
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...
What is Ruby's double-colon `::`?
What is this double-colon :: ? E.g. Foo::Bar .
10 Answers
10
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How do I check if a string is valid JSON in Python?
...print is_json('{"age":100 }') #prints True
print is_json('{"foo":[5,6.8],"foo":"bar"}') #prints True
Convert a JSON string to a Python dictionary:
import json
mydict = json.loads('{"foo":"bar"}')
print(mydict['foo']) #prints bar
mylist = json.loads("[5,6,7]")
print(mylist)
[5, ...
How can I determine if a String is non-null and not only whitespace in Groovy?
...tBlank = { !delegate.allWhitespace }
which let's you do:
groovy:000> foo = ''
===>
groovy:000> foo.notBlank
===> false
groovy:000> foo = 'foo'
===> foo
groovy:000> foo.notBlank
===> true
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Scoping in Python 'for' loops
...ogramming.
In the current situation:
# Sum the values 0..9
total = 0
for foo in xrange(10):
total = total + foo
print total
yields 45. Now, consider how assignment works in Python. If loop variables were strictly local:
# Sum the values 0..9?
total = 0
for foo in xrange(10):
# Create a ...