How do I concatenate strings in arduino? - arduino

sorry I am a bit rusty here, how do I concatenate these 2 outputs?
display.println(timeinfo->tm_hour);
display.println(timeinfo->tm_min);

If you just want them to appear in the output one after another on the same line then use print instead of println for the first one. Println adds a newline to the end of the output and print doesn't. It's always good to look stuff like that up before using a function.
If you really want them put together into one string then you will have to show where those strings are coming from. If they are String class objects you can just use + to put them together. If they are proper c-style strings then you will need to use strcat.

How are defining them?
If you have initialized as arrays of characters:
Example: char exampleCString[50] = "This is a C string";
Then you can use strcat() function in C:
strcat(str1,str2);
Note: Make sure "str1" buffer is big enough, because the result goes there.
If on the other hand, you have initialized your strings as objects of String class:
Example: String exampleJavaString="This is a Java String example"
Then just use the + operator to add them:
str1=str1+str2:

Related

Optimized way to write a series strings to a text file without quotations

I am new to Julia so sorry if this question is obvious.
I am trying to use Julia to help me run a series of finite element models, which use a text input file to give instructions to the finite element solver. Basically, I would like to use Julia to read in the base input file, edit some parameters on some lines of the file and then write it as a new file. I am getting hung up on a couple things though.
Currently, I am reading in the file like this
mdl = "fullmodelSVTV"; #name of input file
A = readlines(mdl*".inp")
This read each line from the file in as a separate string in a vector which I like because it makes it easier to edit the sections I want but it also makes things more difficult when I try to write to a new file.
I am writing the file like this.
io = open("name.inp","w")
print(io,A)
close(io)
When I try to write to a new file the output ends up look like this
Output from code
which is ["string at index 1","string at index 2","string at index 3"...].
What I would like to do is output this the exact same way is it is read in with string at each index of the vector on its own line. I would also like to remove the brackets and quotation marks from the file, as they might interfere with the finite element solver.
I think I have found a way to concatenate all of the strings at each index and separated them with a new line like shown below.
for i in 1:length(A)
conc = conc*"\n"*lines[i]
end
The issue with this is that it takes a long time to do given the size of the input files I am working with and I feel like there has to achieve my goal.
I also cannot find a way to remove the brackets or quotation marks when writing the file.
So, I'm wondering if anyone has any advice for a better way to write these text files in terms of both concatenating all of the strings from the vector when outputting as well as outputting without the brackets and quotation marks.
Thanks, any advice is appreciated.
The issue with print(io,A) is that it is printing a representation of the vector, but in fact you want to print each element of the vector. To do so, you can simply print each line in a loop:
open("name.inp", "w") do io
for line in A
println(io, line)
end
end
This avoids the overhead of string concatenation.

Qt - QString Numerical Format String (cformat), Options?

I have user-provided format string (e.g. "%.2f") and a QVariant type that I am attempting to combine to output into a (formatted) string.
I had gone down the path of using QString::asprintf(const char *cformat, ...) to achieve this, where I would supply the appropriate converted data type, like this:
QString result_str = QString::asprintf(disp_fmt.toUtf8(),variant_type.toUInt());
This works fine for the most part, especially when I have a floating point as the input. However, if my format string in this particular integer (.toUInt()) conversion case includes decimal formatting (e.g. "%.2f"), then I get a constant result of "0.00". This caught me by surprise as I expected to instead just get ".00" tacked onto the integer, as I have seen in other languages like Perl.
What am I missing here? Also, I know asprintf() was added fairly recently and the documentation already now advises to use QTextStream or arg() instead. I don't believe this to be an option, however, for me to use this style of format string. Thanks.
The format string is expecting a double, but you're providing an int. It works if you provide an actual double, like this:
QString result_str = QString::asprintf(disp_fmt.toUtf8(),variant_type.toDouble());
Also note, this behavior is identical to how the standard C library functions work (std::sprintf, etc).

How to extract a substring from main string starting from valid uuid using lua

I have a main string as below
"/tmp/xjtscpdownload/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
From the main string i need to extract a substring starting from the uuid part
"/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
I tried
string.match("/tmp/xjtscpdownload/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/", "/[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}/(.)/(.)/$"
But noluck.
if you want to obtain
"/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
from
"/tmp/xjtscpdownload/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
or let's say 7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0, output and 9999.317528060546245771146821638997525068657 as this is what your pattern attempt suggests. Otherwise leave out the parenthesis in the following solution.
You can use a pattern like this:
local text = "/tmp/xjtscpdownload/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
print(text:match("/([%x%-]+)/([^/]+)/([^/]+)"))
"/([^/]+)/" captures at least one non-slash-character between two slashs.
On your attempt:
You cannot give counts like {4} in a string pattern.
You have to escape - with % as it is a magic character.
(.) would only capture a single character.
Please read the Lua manual to find out what you did wrong and how to use string patterns properly.
Try also the code
s="/tmp/xjtscpdownload/7eb17cc6-b3c9-4ebd-945b-c0e0656a33f0/output/9999.317528060546245771146821638997525068657/"
print(s:match("/.-/.-(/.+)$"))
It skips the first two "fields" by using a non-greedy match.

Add a newline to a string in Scilab

Create a simple string in Scilab containing a newline.
Seems simple enough, but Scilab only seems to interpret escape sequences through printf style functions and msprintf / sprintf splits the string into a vector of strings at the newline!
The only way I can see to achieve this is to actually write a newline out to a file and read it back in again. Surely there is a simpler way to do this!
Ok, found it. The ascii function will do the job, a newline can be added via its ascii decimal -
str = 'hello' + ascii(10) + 'world'

shell - Insert a character at different indexes in a string

It will eventually be part of a larger script so it needs to be shell scripted. A simple task in other languages, but I'm having trouble accomplishing it in shell. Basically I have a string and I want to insert a "." at all possible indices within the string. The output can be on newlined or separated by spaces. Can anyone help?
Example:
input: "abcd"
output: ".abcd
a.bcd
ab.cd
abc.d
abcd."
OR
output: ".abcd a.bcd ab.cd abc.d abcd."
A simple for loop would do:
input=abcd
for ((i=0; i<${#input}+1; i++))
do
echo ${input::$i}.${input:$i}
done
This just slices up the string at each index and inserts a .. You can change the echo to something else like appending to an array if you want to store them instead ouf output them, of course.

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