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Returning a boolean from a Bash function
...; then echo "is directory"; else echo "nopes"; fi
Edit
From @amichair's comment, these are also possible
isdirectory() {
if [ -d "$1" ]
then
true
else
false
fi
}
isdirectory() {
[ -d "$1" ]
}
share
...
Efficient string concatenation in C++
...
Note: "STL" refers to a completely separate open-source library, originally by HP, some part of which were used as a basis for parts of the ISO Standard C++ Library. "std::string", however, was never part of HP's STL, so it's completely wrong to re...
When should you use constexpr capability in C++11?
...
Suppose it does something a little more complicated.
constexpr int MeaningOfLife ( int a, int b ) { return a * b; }
const int meaningOfLife = MeaningOfLife( 6, 7 );
Now you have something that can be evaluated down to a constant while maintaining good readability...
How to wait for several Futures?
...
You could use a for-comprehension as follows instead:
val fut1 = Future{...}
val fut2 = Future{...}
val fut3 = Future{...}
val aggFut = for{
f1Result <- fut1
f2Result <- fut2
f3Result <- fut3
} yield (f1Result, f2Result, f3Resul...
How to create local notifications?
...
}
The way you use to work with Local Notification in iOS 9 and below is completely different in iOS 10.
Below screen grab from Apple release notes depicts this.
You can refer apple reference document for UserNotification.
Below is code for local notification:
Objective-C:
In App-delegate....
Static methods in Python?
...wed in other languages, but it is anyway considered a bad practice and the compiler always warns about it
– SomethingSomething
May 22 '17 at 15:40
...
Summarizing multiple columns with dplyr? [duplicate]
...38 2.873786
#> 3: 3 2.854701 2.948718 2.951567 3.062678
Let's try to compare performance.
library(dplyr)
library(purrrlyr)
library(data.table)
library(bench)
set.seed(123)
n <- 10000
df <- data.frame(
a = sample(1:5, n, replace = TRUE),
b = sample(1:5, n, replace = TRUE),
c = sam...
How do I force Postgres to use a particular index?
...
Assuming you're asking about the common "index hinting" feature found in many databases, PostgreSQL doesn't provide such a feature. This was a conscious decision made by the PostgreSQL team. A good overview of why and what you can do instead can be found her...
iOS UIImagePickerController result image orientation after upload
...size.height,
CGImageGetBitsPerComponent(self.CGImage), 0,
CGImageGetColorSpace(self.CGImage),
CGImageGetBitmapInfo(self.CGImage));
CGContextConcatCTM(ctx, transf...
Difference between Hashing a Password and Encrypting it
...th the specific property that not only the hash be non-reversable BUT ALSO computationally impractical to generate ANY other string that generates the same hash.
– Tall Jeff
Nov 28 '08 at 21:25
...