pest | pest is general purpose parser written in Rust | Parser library

I feel like I'm completely missing out on something but my compiler shows absolutely nothing when i test out if my array is getting filled with values from the txt file.

I try to create an app in Shiny and all selectInput were dynamic reactive objects but at the moment they make some plot (output$myplot) with the combination of the variables select and if(){} condition using observe({}), my plot doesn't work (PEST == unique(stands_ds$PEST) : length of larger object is not multiple of length of smaller object). The problem is with the final selection object selectedvariable4 and try to used selectedvariable4, selectedvariable4(),selectedvariable4()$ID_UNIQUE and unique(selectedvariable4()$ID_UNIQUE) without success. In my example:

I try to create an app in Shiny and all selectInput were dynamic reactive objects but at the moment they make some plot (output$myplot) with the combination of the variables select, my plot doesn't work (Error in charToDate: character string is not in a standard unambiguous format). The problem is with the final selection object selectedvariable4 and try to used selectedvariable4, selectedvariable4(),selectedvariable4()$ID_UNIQUE and unique(selectedvariable4()$ID_UNIQUE) without success. In my example:

Given two strings s1 and s2, we have to check if s2 is a substring of s1. If it's true print "true" else print "false" But s1 and s2 can contain characters like '*' and '\'. In s2, '*' represents zero or more characters in between two alphabets and '\' represents an escape sequence for '*'. In s1, '*' and '\' are just other characters that are to be checked.

Sample Input and Output:

I have an if statement condition for my plots and I need to use observe function. All the app works OK, but when I try to use the shinymanager for credentials creation, my app doesn't work anymore and the error is always: Error in if: argument has length zero

I'd like to use my currentvariable5() reactive object to create some kind of plot if == "A" ( if(currentvariable5()=="A"){}) and another if == "B" (else{}). But I try many tricks in several posts and the output is always:

I have data that looks like this:

[image showing what I need to create

I have to make a program which checks two txt files and concatenates the lines which start with the same ID. The results must be in a new file The files are in the following format:

ID STRING_UP_TO_30_CHARS

Error checking is not necessary but I have been stressing over this for quite a while now. I'm pretty new to programming in general as I am a freshman in University.

Code that I have right now: