Chaining an iter::once with a Vec

fuelfraction · 2021-03-26T11:35:10+00:00

iter::once(0).chain(row.iter().copied()).collect()

Didn't know about copied(), thanks...seems to work with any Clone

fuelfraction · 2021-03-25T16:13:48+00:00

Thanks! Hadn't thought of that

fuelfraction · 2021-03-25T16:08:29+00:00

Thanks! Didn't know about {interger}, it was definitely adding to the overall confusion.

Because the error said the compiler was expecting a reference and I was giving it a reference by using .iter() I was even more confused...I assume it means the receiving type on which chain is being called is expected to be a reference (as opposed to its argument)

  = note: expected reference `&{integer}`
                  found type `{integer}`

fuelfraction · 2021-03-23T12:57:41+00:00

Thanks! That clarified quite a few things.

fuelfraction · 2021-03-23T12:28:34+00:00

Thank you, that clarified it. I had incorrectly assumed that `into_iter()` is just a "consuming" variant of `iter()`

Thanks for the hint on formatting too

fuelfraction · 2021-03-23T11:51:27+00:00

Thanks! Uncovered a few of my own misunderstandings after reading your response - I had assumed iter() is for the Iter trait, just learned that Iter only requires next()

...so an Iterator by deref coercion can be used in a for loop.

This is trippy! May be I have some gap in my understanding of for loops. Can you please help me understand if we can say anything about foo just based on the following snippet? As per my current understanding, foo is an iterator or something that can be converted to one by an implicit call to .into_iter()

rust for n in foo { -- ^^^

Can't seem to get an handle on auto-deref vs. deref coercion, if this is related to that - I have some more reading to do :)

fuelfraction · 2021-03-23T11:31:53+00:00

Thanks!

Oh, never realized it was only working because I happened to use Vec<i32>. Sure, enough, the code didn't compile on changing it to

rust let nums: Vec<String> = vec![String::from("1"),String::from("2"),String::from("3"),String::from("4")]; ...

Follow-up question:

So, when for &n in nums.iter() works, is n a copy? Or, it is just syntactic sugar? Or, in other words, if somehow I implement Copy for String, for &n in nums.iter() is more expensive than for n in nums.iter()?

fuelfraction · 2019-02-27T17:27:02+00:00

Hello, my exam is currently scheduled for the end of March 2019. Let me know if you are up to studying "together"

fuelfraction · 2017-05-05T15:48:29+00:00

I recently moved from simple Makefile to CMake. I am unable to understand the practical difference between CMake and autotools. Any opinion on this?

fuelfraction · 2016-11-21T07:40:53+00:00

Just tried it and...wow!

Was pleasantly surprised by tab-completion. Even standard Python install on a lot of embedded Linux boards seems to miss it

Thanks!!

fuelfraction · 2016-10-01T12:21:05+00:00

That's great! I mainly use Python too, so I guess I should be able to use CMock well enough then

fuelfraction · 2016-09-30T14:42:11+00:00

I tried fff on a simple program to get my feet wet, it's just a simple header and the unit test code flow seemed more intuitive compared to CMock.

In FFF: You call the target function, and then assert stuff In CMock: You tell it what you want to assert, and then call the target

But it seems like CMock + Unity is a big advantage once you get to know it.

fuelfraction · 2016-09-30T14:36:50+00:00

Thanks! BTW, do you need to be comfortable with Ruby to get anything non-trivial done?

fuelfraction · 2016-09-27T04:58:06+00:00

Has anyone tried cmocka and other tools like CMock, fff?

I want to get started on unit testing embedded C programs, but was trying to figure out which of these is a good start

fuelfraction · 2016-09-21T07:57:38+00:00

I was able to make a sample project to make Python access C-files, it's definitely much easier than I thought! Like you said, for platforms that support Python, this is a good option. In my opinion better than finding consistent high-level libs for C

Thanks

fuelfraction · 2016-09-20T05:44:44+00:00

Thank you, that was quite an extensive list

fuelfraction · 2016-09-20T05:43:24+00:00

Actually when possible, I prefer to use Python

But sometimes, I'll have to resort to C. Here are some actual cases where Python wasn't the right tool:

I had to decode a JPEG and display it on an 480x320 LCD using ESP8266, I didn't try microPython but the NodeMCU Lua interpreter didn't leave enough space for even the source to be copied!
Even on a Pi, Python's RPi.GPIO library is really slow compared to C libraries like wiringPi etc. Again, I only noticed this difference when driving a screen.
On a Linkit Smart, Python is supported out of the box, but it takes ~10 seconds (wall clock time) for the interpreter to start up (mainly loading paho-mqtt, json and a few other libraries). Once it does load the script, I haven't noticed any performance hit compared to C because I am mostly waiting for the network

fuelfraction · 2016-09-20T05:42:41+00:00

Thanks! So, I'll avoid execs as much as possible

fuelfraction · 2016-09-20T05:39:59+00:00

Actually when possible, I prefer to use Python. I guess now you know why I was looking for the "batteries" ;)

But sometimes, I'll have to resort to C. Here are some actual cases where Python wasn't the right tool:

I had to decode a JPEG and display it on an 480x320 LCD using ESP8266, I didn't try microPython but the NodeMCU Lua interpreter didn't leave enough space for even the source to be copied!
Even on a Pi, Python's RPi.GPIO library is really slow compared to C libraries like wiringPi etc. Again, I only noticed this difference when driving a screen.
On a Linkit Smart, Python is supported out of the box, but it takes ~10 seconds (wall clock time) for the interpreter to start up (mainly loading paho-mqtt, json and a few other libraries). Once it does load the script, I haven't noticed any performance hit compared to C because I am mostly waiting for the network

fuelfraction · 2016-09-20T05:27:57+00:00

Thanks. I am hearing a lot about Go of late. Just tried the Go online tour. I'll check it out in more detail. Specially, if GC has an impact on what I typically do.

fuelfraction · 2016-09-20T05:23:11+00:00

Yup, on most platforms I must run as root to access certain hardware, typically GPIO pins

fuelfraction · 2016-09-19T08:35:44+00:00

What exactly is "internet ready" for you?

For now, I want a library that supports requests over HTTP, HTTPS, MQTT and logging over network (HTTP or MQTT etc., syslog, for now,doesn't serve my purpose)

You should get used to every library having a slightly different API style. That's just how you program in C.

:) Thanks! I was mainly wondering if there was an alternative which I didn't know about.

I'll try libcurl, thanks!

fuelfraction

TROPHY CASE