I am learning from the book Learn Python The Hard Way 3.6, by Zed Shaw
There are a series of 6 target.write commands towards the bottom of the script and he wants me to simplify them into a single target.write command using strings formats and escapes. However, I am stuck.
Here is the original code:
from sys import argv
script, filename = argv
print(f"We're going to erase {filename}")
print("If you don't want that, hit CTRL-C (^C).")
print("If you do want that, hit RETURN.")
input("?")
print("Opening the file...")
target = open(filename,'w')
print("Truncating the file. Goodbye!")
target.truncate()
print("Now I'm going to ask you for three lines")
line1 = input("line 1:")
line2 = input("line 2:")
line3 = input("line 3:")
print("Im going to write these to the file.")
target.write(line1)
target.write("\n")
target.write(line2)
target.write("\n")
target.write(line3)
target.write("\n")
print("And finnaly, we close it")
target.close()
So far I have tried
target.write(line1),(line2),(line3)
but this gives a logical error of only writing to one line not all three.
target.write(line1) + (line2) + (line3)
with this one I get error
'unsupported operand types for +: 'int' + 'str'
target.write(line1),\n,(line2)\n(line3),\n
with this one I get error:
unexpected character after line continuation character
(<string>,line 22)
I have been googling and searching here for answers but have not found anything. One person posted a very similar question except for Zed's 2.7 book. However I am reading Zed's 3.6 book so the answers were no help to me unfortunately.
I'm not sure what you have and haven't covered so far in the book as I'm not familiar with it but one way to do what you want is to format the string first and then pass it to the write method like this:
target.write("{0}\n{1}\n{2}\n".format(line1, line2, line3))
Related
This is likely a stupid question but I have not found a work around (at least in anything I have searched for, though I might just not be using the right search parameters.)
I want to call an executable in Windows, and send a file to it (in this case a Blaise man file), the name of which is variable in my script.
So, for example, I have
x<-2
myfile<-c(paste("FileNumber",x,".man", sep="")
system("myapp.exe" myfile)
But I simply get
Error: unexpected symbol in "system("myapp.exe" myfile"
as if the command is not recognizing the object as myfile, instead taking "myfile" as literal text.
I tried using a paste function to create a whole line command, but that also did not work.
The system command will not concatenate the string and the myfile object together, you have to do it yourself.
So, try this instead:
x<-2
myfile<-c(paste("FileNumber",x,".man", sep=""))
cmd <- paste("myapp.exe", myfile)
system(cmd)
Or just:
x<-2
system(paste("myapp.exe", c(paste("FileNumber",x,".man", sep=""))))
I am a intern trying to write my first Syntax using Rascal.
While programming i ran into an error that my tutor, Riemer van Rozen, had never seen before. At the moment i am still trying to see if the problem is my code or a Rascal bug but i felt like i should report the error here.
The syntax used to parse normally and even after putting the code back the way it was before I added new stuff it still gives the same error.
My Syntax file
module Syntax
lexical Natural = [0-9]+ !>> [0-9] ;
lexical ID = [a-zA-Z][a-z0-9A-Z]* !>> [a-z0-9A-Z];
lexical String = "\"" ![\"]* "\"";
lexical Sym = [a-zA-Z.!##$%^&*];
lexical Mp = Sym*;
layout WhiteSpace = [\t-\n \r]* ;
start syntax CreatorData
= title: "title " ID title
| author: "author " ID author
| homepage: "homepage " ID homepage;
Parser
module Parser
import Syntax;
import AST;
import ParseTree;
public CreatorData load(str txt) = parse(#CreatorData, txt);
The Error
I hope someone can tell me where i am breaking my program or that i pointed out an unknown Rascal bug.
Call failed means that the call of parse failed, since the arguments you supplied, did not match any of the possible overloads of parse.
For your code, it looks like you also have an ADT called CreatorData. This is overlapping with the CreatorData syntax definition. There is a pattern documented in the tutor how to work around this challenge.
Not sure about your case, but often you can skip the ADT form, and just work on the concrete trees, but that might be something to explore in the future.
I have a text file that contains some basic passwords and some variants of those basic passwords. They are typed out together like this:
qwerty, qwerty1
password, password1
default, default 1
123, 12345, 123456
I am trying to take these values and split them, storing them in a tuple and then print out the values as 'Password' and then any variants, but I am getting a syntax error on the print BIF? (I am aware this will not print out the password '123456', I am just trying to solve the syntax error first.)
for each_line in passwords:
(passwd, passwd_variant) = each_line.split(',',1)
print(f'Password: {passwd}, Variant {passwd_variant}')
SyntaxError: invalid syntax
normally if I was writing a script, in the editor I would put print on a new line, however a new line in IDLE simply executes the code above it. is there a shortcut or something to do a carriage return and write the print statement on a new line and if so, is that the cause of the syntax error and why?
Cheers
EDIT: I would like my output to be this
Finally discovered that you need to hit Enter after the for in statement, this will then take you to a new line inside for in statement. Was up all night trying to work it out, maybe my fresh brain helped this morning.
I have read these SO posts on getting rstudio to print out without truncating:
list output truncated - How to expand listed variables with str() in R
avoid string printed to console getting truncated (in RStudio)
The answers there involve making a adjustment to studio settings which would then cover all future outputs to the console.
Is there a ad hoc way to get r to print an entire string to the console?
I tried:
library(tidyverse)
library(foreach)
mystring <- foreach(i = 1:52) %do% {
paste0("'_gaWeek",i,"'!A16:B;")
} %>% unlist %>% toString()
print(mystring, len = length(mystring))
> print(mystring, len = length(mystring))
[1] "'_gaWeek1'!A16:B;, '_gaWeek2'!A16:B;, '_gaWeek3'!A16:B;, '_gaWeek4'!A16:B;, '_gaWeek5'!A16:B;, '_gaWeek6'!A16:B;, '_gaWeek7'!A16:B;, '_gaWeek8'!A16:B;, '_gaWeek9'!A16:B;, '_gaWeek10'!A16:B;, '_gaWeek11'!A16:B;, '_gaWeek12'!A16:B;, '_gaWeek13'!A16:B;, '_gaWeek14'!A16:B;, '_gaWeek15'!A16:B;, '_gaWeek16'!A16:B;, '_gaWeek17'!A16:B;, '_gaWeek18'!A16:B;, '_gaWeek19'!A16:B;, '_gaWeek20'!A16:B;, '_gaWeek21'!A16:B;, '_gaWeek22'!A16:B;, '_gaWeek23'!A16:B;, '_gaWeek24'!A16:B;, '_gaWeek25'!A16:B;, '_gaWeek26'!A16:B;, '_gaWeek27'!A16:B;, '_gaWeek28'!A16:B;, '_gaWeek29'!A16:B;, '_gaWeek30'!A16:B;, '_gaWeek31'!A16:B;, '_gaWeek32'!A16:B;, '_gaWeek33'!A16:B;, '_gaWeek34'!A16:B;, '_gaWeek35'!A16:B;, '_gaWeek36'!A16:B;, '_gaWeek37'!A16:B;, '_gaWeek38'!A16:B;, '_gaWeek39'!A16:B;, '_gaWeek40'!A16:B;, '_gaWeek41'!A16:B;, '_gaWeek42'!A16:B;, '_gaWeek43'!A16:B;, '_gaWeek44'!A16:B;, '_gaWeek45'!A16:B;, '_gaWeek46'!A16:B;, '_gaWeek47'!A16:B;, '_gaWeek48'!A16:B;, '_gaWeek49'!A16:B;, '_gaWeek50'!A16:B;, '_ga... <truncated>
It's truncated. Is there an ad hoc way around this without changing rstudio settings? Such as by a function argument? I tried print() here.
Also, how do I get rid of the comma separator in between each instance above?
The short answer is "no" since, the option limiting the print is in the IDE itself, which you can't control from your program itself (I'm assuming you're not some crazy hacker here), and not a language feature. It's like trying to stop "WINDOWS" from doing things (although not).
Seems to me the easiest way (ad hoc) is to turn it on, do whatever, then turn it off. If you insist on not doing that, you need to write your own function:
myprint<- function(somestring,idelimit=100) {
for(i in seq(1,nchar(somestring),idelimit+1)) {
print(substr(somestring,i,i+idelimit));
}
}
I'm not a fluent R coder so let me know if you catch a syntax error. The idea is simple - idelimit should be wherever studio truncates (I chose 100 arbitrarily), and basically you're doing the splitting yourself so string is printed line after line without truncation. Each time you take a portion at most idelimit long from somestring and print it.
I have a list of netcdf files that I am trying to concatenate along the time dimension.
I am attempting to use the steps outlined here, which seem simple enough. However, I am running into some errors (likely some small/stupid oversight on my part...)
When I try to first make time a record dimension, I am using the following command:
ncks -O --mk_rec_dmn time TiMREX_20080526_000001.nc test_out.nc
This, however, give me the following error:
ncks: invalid option -- '-'
It seems like this is just some simple syntax/typo error on my part, but try as I might I can' find anything wrong.
Just to be sure, when I run a ncdump -h on the file, it confirms that there is indeed a time dimension
ncdump -h TiMREX_20080526_000001.nc
netcdf TiMREX_20080526_000001 {
dimensions:
time = 1 ;
bounds = 2 ;
x0 = 300 ;
y0 = 300 ;
z0 = 40 ;
Additionally, if I try to skip this step and just go right to the ncrcat part...
ncrcat -O TiMREX_20080526_000001.nc TiMREX_20080526_000733.nc test_out.nc
I get the following error:
ncopen: filename "TiMREX_20080526_000001.nc": Not a netCDF file
Which is especially odd...I'm pretty confident it is indeed at netCDF file (I just ran ncdump on it after all, and have no problem viewing it with ncview...)
Any thoughts? What simple step am I embarrassingly missing?
This is a weird error as your command looks syntactically correct. To be sure, I copied it to my machine where it ran as expected, with no 'invalid option' error. Thus I am unable to reproduce the problem. Based on the error message you report, it seems as though you might (somehow) be using a character that the system does not understand as a dash. In other words, the error you report is what I would expect if ncks received a funky character that looks like a dash but is not really a dash. Maybe when you copy it to stackoverflow it gets converted to a dash, so it works for me (try copying your own command above back into your console). Make sure the dash character you type is the same as the minus sign on a normal keyboard, and something else. Some keyboard/character sets make characters that look similar to dashes but are not ASCII dashes. Good luck.