fn | Functional library for PHP | Functional Programming library
kandi X-RAY | fn Summary
kandi X-RAY | fn Summary
Yet another functional library for PHP. What makes this library special is that it uses PHP Parser to generate curried versions of the non-curried implementations for best performance.
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Top functions reviewed by kandi - BETA
- argument 2 .
- Calculate the argument 3 .
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Trending Discussions on fn
QUESTION
In the current stable Rust, is there a way to write a function equivalent to BTreeMap::pop_last?
The best I could come up with is:
...ANSWER
Answered 2022-Mar-15 at 16:55Is there a way to work around this issue without imposing additional constraints on map key and value types?
It doesn't appear doable in safe Rust, at least not with reasonable algorithmic complexity. (See Aiden4's answer for a solution that does it by re-building the whole map.)
But if you're allowed to use unsafe, and if you're determined enough that you want to delve into it, this code could do it:
QUESTION
I am trying to do a regular import in Google Colab.
This import worked up until now.
If I try:
ANSWER
Answered 2021-Oct-15 at 21:11Found the problem.
I was installing pandas_profiling, and this package updated pyyaml to version 6.0 which is not compatible with the current way Google Colab imports packages.
So just reverting back to pyyaml version 5.4.1 solved the problem.
For more information check versions of pyyaml here.
See this issue and formal answers in GitHub
##################################################################
For reverting back to pyyaml version 5.4.1 in your code, add the next line at the end of your packages installations:
QUESTION
Consider following code
...ANSWER
Answered 2022-Mar-03 at 21:14You are correct, this is due to match ergonomics. The first case should hopefully be self explanatory, but the second and third cases can be a bit counter-intuitive.
In the second case:
(x,)is a non-reference pattern (see the second example in the RFC). Thettuple reference is dereferenced, andxis bound as arefas it also is a non-reference pattern. Note thatt.0was a reference to begin with, thus resulting inxbeing a double reference.(&y,)is also a non-reference pattern. Thettuple is dereferenced again to a(&i32,). However,&yis a reference pattern being matched to a&i32reference. Henceyis bound withmovemode and is ani32.
In the third case:
Using the same reasoning as the second case,
uis dereferenced viaDerefcoercion to an(i32,), andx, a non-reference pattern, is bound inrefmode. Hencexis an&i32.Again with the same reasoning as the second case,
uis dereferenced to an(i32,). The&yreference pattern is then matched to ani32, a non-reference, which causes an error.
QUESTION
I have been using the #[tokio::main] macro in one of my programs. After importing main and using it unqualified, I encountered an unexpected error.
ANSWER
Answered 2022-Feb-15 at 23:57#[main] is an old, unstable attribute that was mostly removed from the language in 1.53.0. However, the removal missed one line, with the result you see: the attribute had no effect, but it could be used on stable Rust without an error, and conflicted with imported attributes named main. This was a bug, not intended behaviour. It has been fixed as of nightly-2022-02-10 and 1.59.0-beta.8. Your example with use tokio::main; and #[main] can now run without error.
Before it was removed, the unstable #[main] was used to specify the entry point of a program. Alex Crichton described the behaviour of it and related attributes in a 2016 comment on GitHub:
Ah yes, we've got three entry points. I.. think this is how they work:
- First,
#[start], the receiver ofint argcandchar **argv. This is literally the symbolmain(or what is called by that symbol generated in the compiler).- Next, there's
#[lang = "start"]. If no#[start]exists in the crate graph then the compiler generates amainfunction that calls this. This functions receives argc/argv along with a third argument that is a function pointer to the#[main]function (defined below). Importantly,#[lang = "start"]can be located in a library. For example it's located in the standard library (libstd).- Finally,
#[main], the main function for an executable. This is passed no arguments and is called by#[lang = "start"](if it decides to). The standard library uses this to initialize itself and then call the Rust program. This, if not specified, defaults tofn mainat the top.So to answer your question, this isn't the same as
#[start]. To answer your other (possibly not yet asked) question, yes we have too many entry points.
QUESTION
I am using MongoDB(Mongo Atlas) in my Django app. All was working fine till yesterday. But today, when I ran the server, it is showing me the following error on console
...ANSWER
Answered 2021-Oct-03 at 05:57This is because of a root CA Let’s Encrypt uses (and Mongo Atals uses Let's Encrypt) has expired on 2020-09-30 - namely the "IdentTrust DST Root CA X3" one.
The fix is to manually install in the Windows certificate store the "ISRG Root X1" and "ISRG Root X2" root certificates, and the "Let’s Encrypt R3" intermediate one - link to their official site - https://letsencrypt.org/certificates/
Copy from the comments: download the .der field from the 1st category, download, double click and follow the wizard to install it.
QUESTION
Is there a more idiomatic way to express something like the following?
...ANSWER
Answered 2022-Jan-27 at 07:32There are many ways to do it. One of the simplest (and arguably most readable) is something like this:
QUESTION
I'm trying to adapt some layers of existing C++ code to be used by Rust and apparently the way is through a C API.
For example, one function might return a struct as an object
...ANSWER
Answered 2022-Jan-21 at 01:15extern "C" on both sides + #[repr(C)] on the Rust side + only using C-compatible types for interfacing between C++ and Rust, should work.
QUESTION
I have read several answers on SO already, and gathered these use-cases:
- When a function
panic!s - When a function has an infinite loop in it
But it is still unclear to me why we need to define the function like this:
...ANSWER
Answered 2022-Jan-22 at 13:23The main difference between these signatures boils down to the fact that ! can coerce into any other type, and thus is compatible with any other type (since this code path is never taken, we can assume it to be of any type we need). It's important when we have multiple possible code paths, such as if-else or match.
For example, consider the following (probably contrived, but hopefully clear enough) code:
QUESTION
These two loops are equivalent in C++ and Rust:
...ANSWER
Answered 2022-Jan-12 at 10:20Overflow in the iterator state.
The C++ version will loop forever when given a large enough input:
QUESTION
fn main() {
let arr: [u8;8] = [97, 112, 112, 108, 101];
println!("Len is {}",arr.len());
println!("Elements are {:?}",arr);
}
ANSWER
Answered 2021-Oct-05 at 05:31You can use concat_arrays macro for it:
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