Develop Reference

Python placeholders in read text

I am fairly new to Python, teaching it to myself by watching tutorials and doing the trial and error kind of thing, and I ran into a task, which I am not able to solve right now:
I am reading from a file with following code:
def read_file(file):
try:
with open(file) as f:
content = f.read()
return content
except FileNotFoundError:
print("\nThis file does not exist!")
exit()
The file(.txt) I am reading contains a text with multiple placeholders:
Hello {name}, you are on {street_name}!
Now I want to replace the placeholders {name} and {street_name} with their corresponding variables.
I know how f-strings work. Can this somehow be applied to this problem too, or do I have to parse the text to find the placeholders and somehow find out the fitting variable that way?
Each text I read, contains different placeholders. So I have to find out, which placeholder it is and replace it with the according string.

Not sure if that is what you are looking for:
string = "Hello {name}, you are on {street_name}!"
string = string.format(name="Joe", street_name="Main Street")
print(string)
or
string = "Hello {name}, you are on {street_name}!"
name = "Joe"
street_name = "Main Street"
string = string.format(name=name, street_name=street_name)
print(string)
gives you
Hello Joe, you are on Main Street!
See here.
If you actually don't know what placeholders are in the text then you could do something like:
import re
string = "Hello {name}, you are on {street_name}!"
name = "Joe"
street_name = "Main Street"
placeholders = set(re.findall(r"{(\w+)}", string))
string = string.format_map({
placeholder: globals().get(placeholder, "UNKOWN")
for placeholder in placeholders
})
If you know that all placeholders are present as variables, then you could simply do:
string = "Hello {name}, you are on {street_name}!"
name = "Joe"
street_name = "Main Street"
string = string.format_map(globals())

Adding variables to dataclass from json config file

After watching ArjanCodes video on dataclasses,
I've been trying to add variables to a python dataclass from a json config file to format the font style of a print function printT in Jupyterlab.
I use ANSI escapes for the formatting which doesn't work anymore if I import the variables to the dataclass. Instead of formatting the text, the ANSI code get's printed out.
# config.json
{
"lb" : "\n",
"solid_line" : "'___'*20 + config.lb",
"dotted_line" : "'---'*20 + config.lb",
"BOLD" : "\\033[1m",
"END" : "\\033[0m"
}
# config.py
from dataclasses import dataclass
import json
#dataclass
class PrintConfig:
lb : str
solid_line : str
dotted_line : str
BOLD : str
END : str
def read_config(config_file : str) -> PrintConfig:
with open(config_file, 'r') as file:
data = json.load(file)
return(PrintConfig(**data))
# helper.py
from config import read_config
config = read_config('config.json')
def printT(title,linebreak= True,addLine = True, lineType = config.solid_line,toDisplay = None):
'''
Prints a line break, the input text and a solid line.
Inputs:
title = as string
linebreak = True(default) or False; Adds a line break before printing the title
addLine = True(default) or False; Adds a line after printing the title
lineType = solid_line(default) or dotted_line; Defines line type
toDisplay = displays input, doesnt work with df.info(),because info executes during input
'''
if linebreak:
print(config.lb)
print(config.BOLD + title + config.END)
if addLine:
print(lineType)
if toDisplay is not None:
display(toDisplay)
# test.ipynb
from helper import printT
printT('Hello World')
Output
\033[1mHello World\033[0m
'___'*20 + config.lb
Desired result
Hello World
It works if I use eval if addLine: print(eval(lineType)) but I'd like to get deeper insights into the mechanics here. Is there a way of getting it to work without eval?
Also this part "solid_line" : "'___'*20 + config.lb" feels wrong.
Markdown as alternative to ANSI

Here's a basic configuration system. I won't add the output since it would need a screenshot but it works on bash/macos. Inspired by and [tip_colors_and_formatting]
And from (https://misc.flogisoft.com/bash/tip_colors_and_formatting):
In Bash, the character can be obtained with the following syntaxes:
\e
\033
\x1B
\e didn't work, so I went on to use to \x1B since that worked in the linked SE answer. \033 works too, I checked.
from dataclasses import dataclass
PREFIX = "\x1B["
#these aren't configurable, they are ANSI constants so probably
#not useful to put them in a config json
CODES = dict(
prefix = PREFIX,
bold = f"1",
reset = f"{PREFIX}0m",
red = "31",
green = "32",
)
#dataclass
class PrintConfig:
bold : bool = False
color : str = ""
def __post_init__(self):
# these are calculated variables, none of client code's
# business:
self.start = self.end = ""
start = ""
if self.bold:
start += CODES["bold"] + ";"
if self.color:
start += CODES[self.color.lower()] + ";"
if start:
self.end = CODES["reset"]
#add the escape prefix, then the codes and close with m
self.start = f"{CODES['prefix']}{start}".rstrip(";") + "m"
def print(self,v):
print(f"{self.start}{v}{self.end}")
normal = PrintConfig()
normal.print("Hello World")
bold = PrintConfig(bold=1)
print(f"{bold=}:")
bold.print(" Hello World")
boldred = PrintConfig(bold=1,color="red")
print(f"{boldred=}:")
boldred.print(" Hello bold red")
#this is how you would do it from json
green = PrintConfig(**dict(color="green"))
green.print(" Little Greenie")
#inspired from https://stackoverflow.com/a/287934
print("\n\ninspired by...")
CSI = "\x1B["
print(CSI+"31;40m" + "Colored Text" + CSI + "0m")
print(CSI+"1m" + "Colored Text" + CSI + "0m")

This string consists of an actual backslash followed by the digits 033, etc.
"BOLD" : "\\033[1m",
To turn on bold on an ansi terminal, you need an escape character (octal 33) followed by [1m. In Python, you can write those escape codes with a single backslash: "\033[1m". In a json file, you must provide the unicode codepoint of the escape character, \u001b. If the rest is in order, you'll see boldface.
"BOLD" : "\u001b[1m",
"END" : "\u001b[0m"
As for the eval part, you have a string containing the expression you need to evaluate. I assume you wrote it this way because you first tried without the double quotes, e.g. ,
"dotted_line" : '---'*20 + config.lb,
and you got a json syntax error. That's not surprising: Json files are data, not code, and they cannot incorporate expressions or variable references. Either place your config in a python file that you include instead of loading json, or move the dependencies to the code. Or both.
In a python file, config.py:
config = {
"lb": "\n",
"solid_line" : '___'*20,
...
In helper.py:
...
if addLine:
print(lineType + config.lb)

How to escape all HTML entities in show_popup() method and fix Parse Error in Sublime Text 3 plugin?

I am making a plugin for Sublime Text 3. It contacts my server in Java and receives a response in the form of a list of strings, that contains C code.
To display this code in a popup window you need to pass a string in HTML format to the method show_popup. Accordingly, all C-code characters that can be recognized by the parser as HTML entities should be replaced with their names (&name;) or numbers (&#number;). At first, I just replaced the most common characters with replace(), but it didn't always work out - Parse Error was displayed in the console:
Parse Error: <br> printf ("Decimals: %d %ld\n", 1977, 650000L);
<br> printf ("Preceding with blanks:&nbs
...
y</a></li><p><b>____________________________________________________</b></p>
</ul>
</body>
code: Unexpected character
I've tried to escape html entities with Python's html library:
import html
...
html.escape(string)
But Sublime doesn't see import and print in console that I was using a function without defining it - I guess he didn't see that I connected this library(Whyyy?). cgi.escape - is depricated, so I can't use this. I decided to write the function myself.
Then I saw a very interesting way to replace all the characters whose code is >127 and some other characters (&, <,>) with their numbers:
def escape_html (s):
out = ""
i = 0
while i < len(s):
c = s[i]
number = ord(c)
if number > 127 or c == '"' or c == '\'' or c == '<' or c == '>' or c == '&':
out += "&#"
out += str(number)
out += ";"
else:
out += c
i += 1
out = out.replace(" ", " ")
out = out.replace("\n", "<br>")
return out
This code works perfectly for displaying characters in a browser, but unfortunately it is not supported by Sublime Text 3.
As a result, I came to the conclusion that these characters should be replaced with their equivalent names:
def dumb_escape_html(s):
entities = [["&", "&"], ["<", "<"], [">", ">"], ["\n", "<br>"],
[" ", " "]]
for entity in entities:
s = s.replace(entity[0], entity[1])
return s
But again I faced an obstacle: not all names are supported in Sublime. And again an error Parse Error.
I also attach a link to JSON file, which contains answer from my server, content of which should be displayed in pop-up window: Example of data from sever (codeshare.io)
I absolutely do not understand, in what I make a mistake - I hope, that great programmers know how to solve my problem.
Edit. Minimal, Reproducible Example:
import sublime
import sublime_plugin
import string
import sys
import json
def get_func_name(line, column):
return "printf"
def get_const_data(func_name):
input_file = open ("PATH_TO_JSON/data_printf.json")
results = json.load(input_file)
return results
def dumb_escape_html(s):
entities = [["&", "&"], ["<", "<"], [">", ">"], ["\n", "<br>"],
[" ", " "]]
for entity in entities:
s = s.replace(entity[0], entity[1])
return s
def dumb_unescape_html(s):
entities = [["<", "<"], [">", ">"], ["<br>", "\n"],
[" ", " "], ["&", "&"]]
for entity in entities:
s = s.replace(entity[0], entity[1])
return s
class CoderecsysCommand(sublime_plugin.TextCommand):
def run(self, edit):
v = self.view
cur_line = v.substr(v.line(v.sel()[0]))
for sel in v.sel():
line_begin = v.rowcol(sel.begin())[0]
line_end = v.rowcol(sel.end())[0]
pos = v.rowcol(v.sel()[0].begin()) # (row, column)
try:
func_name = get_func_name(cur_line, pos[1]-1)
li_tree = ""
final_data = get_const_data(func_name)
for i in range(len(final_data)):
source = "source: " + final_data[i]["source"]
escaped = dumb_escape_html(final_data[i]["code"])
divider = "<b>____________________________________________________</b>"
li_tree += "<li><p>%s</p>%s <a href='%s'>Copy</a></li><p>%s</p>" %(source, escaped, escaped, divider)
# The html to be shown.
html = """
<body id=copy-multiline>
Examples of using <b>%s</b> function.
<ul>
%s
</ul>
</body>
""" %(func_name, li_tree)
self.view.show_popup(html, max_width=700, on_navigate=lambda example: self.copy_example(example, func_name, source))
except Exception as ex:
self.view.show_popup("<b style=\"color:#1c87c9\">CodeRec Error:</b> " + str(ex), max_width=700)
def copy_example(self, example, func_name, source):
# Copies the code to the clipboard.
unescaped = dumb_unescape_html(example)
unescaped = "// " + source + unescaped
sublime.set_clipboard(unescaped)
self.view.hide_popup()
sublime.status_message('Example of using ' + func_name + ' copied to clipboard !')

probleme with old python scrip

I'm still republishing a python 2.x script in 3.x.
at some point, the script must replace the "print" function with "disp" (equivalent in TI basic language) except that it no longer works because of parentheses. anyone have an idea to fix it?
The code :
elif (line.find("print ")==idepth(line)):
line = replace(line,"print ","Disp ")
if (line[-1] == ","):
line = line[:-1].rstrip() # Trailing , not legal for ti basic
thanks in advance
Edit: full code :
import sys
import os
import re
#GUI:
import tkinter as tk
from tkinter import filedialog
import tkinter.simpledialog
import tkinter.messagebox
GUI_MODE = False
TAB_REPLACE = " "
def main():
args = sys.argv[1:]
global GUI_MODE
print (args)
if (len(args)==0):
GUI_MODE=True
root = tk.Tk()
root.withdraw()
inp = filedialog.askopenfilename(title="Select a python script to convert")
if (inp==''):
print ("cancelled")
return 0
else:
inp=args[0]
#now input file is known
file=open(inp)
prog = file.read().replace("\r","").split("\n") # Lines of code
#Get a program name:
if (prog[0][:1]=="#" and (prog[0].upper().find("NAME:")>-1 or prog[0].upper().find("PROGRAM:")>-1 )):
outname=prog[0][prog[0].find(":")+1:]
else:
outname=tkinter.simpledialog.askstring("File name","What do you want to name this program?")
fixed = format(prog)
#Write the converted program in this folder:
print ("\n--Converted to TI-Basic code:--")
print (fixed)
print ("")
print ("Making output files: "+outname+".tib, "+outname+".8xp ...")
#Write the converted program in this folder:
outfile=open(outname+".tib","w")
outfile.write(fixed)
outfile.close()
#Write the .8xp program
outfile=open(outname+".8xp","w")
outfile.write(fixed)
outfile.close()
#assuming the compiler tibasic.exe is in this folder:
if (sys.platform[:3]=="win"):
if (os.system('tibasic.exe '+outname+'.tib')): #Returns non-0, error:
errReport("Error trying to run tibasic.exe! Make sure it is in the current folder.")
else:
if (os.system('wine tibasic.exe '+outname+'.tib')): #Returns non-0, error:
errReport("Error trying to run tibasic.exe! Make sure it is in the current folder, and w.i.n.e is installed.\n"+
"(See http://www.winehq.org/ for installer)")
os.remove(outname+".tib")
a=input("Done! Press enter to exit:") #pause
return 0
def format(linesArray): #converts lines from Python to ti-basic.
for i in range(len(linesArray)):
linesArray[i]=linesArray[i].replace("\t",TAB_REPLACE) #Important! see idepth()
i=0;
linesArray.append("") # 0-indent ending so blockAddEnd won't mess up.
while (i<len(linesArray)):
#Convert control blocks (if, for, while) from indented (python) to END (TI)
line = linesArray[i]
if isBlockStart(line,"for "):
linesArray = blockAddEnd(linesArray, i, "End")
elif isBlockStart(line,"if "):
linesArray = blockAddEnd(linesArray, i, "End")
elif isBlockStart(line,"while "):
linesArray = blockAddEnd(linesArray, i, "End")
elif isBlockStart(line,"repeat "): #not in python, but works on TI.
linesArray = blockAddEnd(linesArray, i, "End")
i+=1
# Don't need indentations anymore, do the rest of the conversions:
for i in range(len(linesArray)):
linesArray[i]=convLine(linesArray[i],i+1)
#Remove blanks:
for i in range(linesArray.count("")):
linesArray.remove("")
return "\n".join(linesArray)
def convLine(line,num): #Line by line conversion.
line = line.rstrip().lstrip() #trim indentation.
lnum = "Line "+str(num)+": "
if line.count("#"):
comment = line[line.find("#"):]
if (comment[0:6] == "#no-ti"):
#Does not work on the ti.
return ""
elif (comment[0:4] == "#ti:"):
# Only for ti:
return comment[4:]
else:
line = line[:line.find("#")] # take comment off code
#No imports in ti-basic!
if line.startswith("import ") or (line.count(" import ") and line.startswith("from ")):
return ""
#Errors and warnings:
if (toolong(line)):
print (lnum+"Warning: Text string too long to fit on a TI83/84 screen. The calculator screen is 16 characters wide, 8 characters high.")
if (line.find("\n")>-1):
print (lnum+"Warning: newline \\n is not allowed in TI-Basic.")
if (line.find("'''")>-1):
print (lnum+"Warning: ''' quotes are not allowed, you must use \" quotes on a single line for TI-Basic.")
if (replace(line,"pow(","")!=line):
errReport(lnum+"TI calculators don't have the pow() command, you must use a**b instead of pow(a,b).")
if (replace(line,"import ","")!=line):
print (lnum+"import ignored. No import statements in TI-Basic!")
return "" # ignore import statements!
if (replace(line,"-=","")!=line):
errReport(lnum+"The -= operator is not allowed.\nTry +=- or a=a+-number instead.")
if (replace(line,"def ","")!=line):
errReport(lnum+"Functions are not supported in TI-Basic! However, you can run another program with \"prgmPRGNAME\".")
if (replace(line,"//","")!=line):
print (lnum+"// division converted to / division: For int division, try int(a/b).")
line=replace(line,"//","/")
if (replace(line,"-","")!=line):
print (lnum+"Warning: The - is changed to negative sign on the calculator. If you wanted to subtract, use a+-b instead of a-b.")
if (replace(line,"open(","")!=line):
errReport(lnum+"Error: TI calculators can't use \"open(filename)\" in programs. To store text, try using variables STR0, STR1, ... STR9.")
if (replace(line,"%","")!=line):
errReport(lnum+"Error: TI83/84 calculators don't have Mod.\n Instead of a % b, try (a/b-int(a/b))*b instead.")
# Replace excess spaces, they cause errors in the calculator:
line=replace(line,", ",",")
line=replace(line," + ","+")
line=replace(line," - ","-")
line=replace(line," +- ","+-")
line=replace(line," * ","*")
line=replace(line," / ","/")
line=replace(line," == ","==")
line=replace(line," > ",">")
line=replace(line," < ","<")
line=replace(line," != ","!=")
#TODO: Arrays converted to lists?
line=replace(line,"theta","[theta]") # variable
line=replace(line,"**","^")
line=mathReplace(line)
#round, max, min already works.
line=replace(line,"float(","(")
line=replace(line,"len(","dim(")
line=replace(line,"math.pi","[pi]")
line=replace(line,"math.e","[e]")
line=replace(line,"eval(","expr(")
line=replace(line,"-","[neg]") # use +- instead of - operator.
line=replace(line,"==","=")
line=replace(line," and ","&")
line=replace(line," or ","|")
line=replace(line,"random.random()","rand")
line=replace(line,"random.randint","RandInt")
line=replace(line,"int(","iPart(")
if (replace(line,"input(","") != line):
line=inputConv(line,num)
if isBlockStart(line,"for "):
line=forConv(line,num)
elif (isBlockStart(line,"if ")):
line = replace(line,"if ","If ")
line = replace(line,":",":Then")
elif (isBlockStart(line,"while ")):
line = replace(line,"while ","While ")
line = replace(line,":","")
elif (isBlockStart(line,"repeat")):
line = replace(line,"repeat","Repeat")
line = replace(line,":","")
elif (isBlockStart(line,"else")):
line = replace(line,"else:","Else")
elif isBlockStart(line,"elif"):
errReport(lnum+"""Error: There is no else-if command on the TI83/84. However, you can use this instead:
if <condition>:
...
else:
if <condition>:
...
else:
...""")
elif (line.find("print ")==idepth(line)):
line = re.sub(r"print *\((.+)\)", r"disp \1", line)
if (line[-1] == ","):
line = line[:-1].rstrip() # Trailing , not legal for ti basic
elif (replace(line,"=","")!=line): #assignment is -> on the calculator.
eqspace = line.find("=")
line = line[eqspace+1:].rstrip().lstrip() + "->" + line[:eqspace].rstrip().lstrip() # sto arrow.
line = fixEQ(line)
return replace(line,"+[neg]","-") #lastly, switch back the negative.
def fixEQ(line):
# fix +=, *=, /=.
# A+=1 changes to 1->A+, so fix it now.
if (line[-1]=="+" or line[-1]=="*" or line[-1]=="/"):
line = line[:-1].rstrip()+line[-1] # remove any spaces in "a +" etc
pre = line[line.find("->")+2:]
#pre = pre[:-1].rstrip()+pre[-1]
line= pre + "("+line[:line.find("->")]+")"+ line[line.find("->"):-1]
return line
def inputConv(line,num):
lnum = "Line "+str(num)+": "
if (replace(line,"raw_input(","")!=line and line==replace(line,"=","")):
#raw_input not assigned to variable is like Pause.
return "Pause "
else:
var = line[:line.find("=")].rstrip().lstrip()
if (len(var)>1 and var!="theta"): # might be invalid.
print (lnum+"Warning: Program tries to store to variable \"%s\"." % var)
prompt = line[line.find("input(")+6:]
prompt = prompt[:prompt.find(")")]
# Now return the TI basic input with var spaces removed:
return "Input "+prompt+","+var
def forConv(line,num):
lnum = "Line "+str(num)+": "
# split "for i in range(...):"
var = line[line.find("for ")+4:line.find(" in range")]
#print var
part = line[line.find("in range(")+9:] # only "...) : "
part = part.rstrip(": ")[:-1] # remove extra " " or ":", remove last ).
#print "'"+line+"'"
out = part.split(",")
if len(out)==1:
return "For(%s,0,(%s)-1)" % (var, out[0])
elif len(out)==2:
return "For(%s,(%s),(%s)-1)" % (var, out[0], out[1])
elif len(out)==3:
return "For(%s,(%s),(%s)-1,(%s)" % (var, out[0], out[1], out[2])
else:
errReport(lnum+"Too many commas in for loop!")
return "couldn't convert: "+line
def blockAddEnd(lines, startLine, endText):
# Takes an array, line #, and end text.
# Adds end for that indentation block.
startInd = idepth(lines[startLine])
if idepth(lines[startLine+1]) <= startInd:
errReport("Expected indent after line "+str(startLine+1)+".")
i = startLine+1
#continue searching for the end while it's indented or it's an else line:
while idepth(lines[i]) > startInd or (isBlockStart(lines[i],"else")):
i+=1
# now insert.
lines.insert(i,endText)
return lines
def idepth(text):
# get indentation depth of line.
depth=0
line = text.replace("\t",TAB_REPLACE) #tab is 4 spaces.
while (line[:1]==" "):
line=line[1:]
depth+=1
return depth
def replace(text, changethis, tothis):
# replaces text, but not in quotes.
arr = text.split("\"")
for i in range(0,len(arr),2):
arr[i]=arr[i].replace(changethis, tothis)
return "\"".join(arr)
def toolong(text):
# checks for too long string:
arr = text.split("\"")
for i in range(1,len(arr),2):
#print arr[i]
if (len(arr[i]) > 16):
return True
return False
def parMatch(text,num): # given "(stuff()...()))", returns the parentheses block.
lnum = "Line "+str(num)+": "
for i in range(len(text)):
part = text[:i-1]
if (part.count("(")==part.count(")")):
return part[1:-1] #without outside parentheses.
errReport(lnum+"Invalid parentheses")
def isBlockStart(line, type):
# Check if the line is start of a <type> block.
# checks if it starts with <type>, and ends with ":".
# example: isBlockStart("for i in range(8) : ","for") is true.
return (line.find(type) == idepth(line) and line.rstrip(" ")[-1]==":")
def errReport(text):
print (text)
if (GUI_MODE):
root = tk.Tk()
root.withdraw()
tkinter.messagebox.showerror("Error",text)
sys.exit(1)
def mathReplace(line):
""" Replaces mathematical functions with ti basic functions. """
#Same function in both Python and TI-basic:
same = ["sin", "cos", "tan", "asin", "acos", "atan", "sinh", "cosh", "tanh", "asinh", "acosh", "atanh"]
line=replace(line,"math.sqrt(","[root]^2(")
line=replace(line,"math.fabs(","abs(")
for func in same:
line = replace(line,"math.%s(" % func,func)
line=replace(line,"math.log(","ln(")
line=replace(line,"math.exp(","e^(")
line=replace(line,"math.floor(","int(")
line=replace(line,"math.log10(","log(")
#same, but without "math." They might use
#from math import sqrt etc...
line=replace(line,"sqrt(","[root]^2(")
line=replace(line,"fabs(","abs(")
for func in same:
line = replace(line, "%s(" % func,func)
#(Redundant lines deleted)
line=replace(line,"log(","ln(")
line=replace(line,"exp(","e^(")
line=replace(line,"floor(","int(")
line=replace(line,"log10(","log(")
return line
if __name__ == '__main__': main()
it's the original code with changement propose below

You can use python's regular expression library to perform more advanced string matching and replacement than replace(). Specifically, re.sub(), which functions the same as replace() but takes regular expressions instead of simple strings.
Be sure to first import it with import re. You can then do the following:
elif (line.find("print ")==idepth(line)):
line = re.sub(r"print *\(\"(.+)\"\)", r"disp \1", line)
if (line[-1] == ","):
line = line[:-1].rstrip() # Trailing , not legal for ti basic
This will look for a string of the format "print("&1")" or "print ("&1")" and replace it with "disp &1", where &1 is the contents between the quotes.
Edit: You had initially specified that you wanted the output "without the quotes", but it seems you've edited that comment. If you want to include the quotes in the output, use this line instead:
line = re.sub(r"print *\((.+)\)", r"disp \1", line)

Python; How to replace escaped non-unicode characters with their respective 'real' utf-8

I am relatively new to programming, and I have a small problem writing a python equivalent of Snip for spotify for ubuntu(linux)
Somehow i can encode the title correctly, but am unable to encode the artist the same way
when i try to encode the artist in the same fashion i get this:
File "./songfinder.py", line 11, in currentplaying
artiststr = str((metadata['xesam:artist']).encode('utf-8'))
AttributeError: 'dbus.Array' object has no attribute 'encode'
however the title is done exactly the same and that is working.
Code so far IS working but has for example \xd8 instead of Ø, and similar:
import dbus
session_bus = dbus.SessionBus()
spotify_bus = session_bus.get_object("org.mpris.MediaPlayer2.spotify", "/org/mpris/MediaPlayer2")
spotify_properties = dbus.Interface(spotify_bus, "org.freedesktop.DBus.Properties")
def currentplaying():
metadata = spotify_properties.Get("org.mpris.MediaPlayer2.Player", "Metadata")
title = str((metadata['xesam:title']).encode('utf-8'))
artiststr = str((metadata['xesam:artist']))
if ("dbus.string" in artiststr.lower()):
artists = artiststr.split("(u")
artist = artists[1]
artists = artist.split(")],")
artist = artists[0]
artist = artist.replace("(u", "")
else:
artist = "'unknown'"
artist = (artist.replace("'",""))
playing = (artist + " - " + title + " ")
return playing
#save playing to file.txt
relevant qna's:
Replace non-ascii chars from a unicode string in Python
Why it does not resolve my problem: I would like to print/save the actual character, not replace it with similar ones

Looking at your question metadata contains at least something like this with Unicode strings. The artist field seems to be some sort of iterable the begins with the artist. Something like this (feel free to post actual metadata content):
metadata = {'xesam:title':u'title','xesam:artist':[u'artist']}
In the title assignment line, str is unnecessary since encoding a Unicode string returns a str anyway, but no need to encode it either. Unicode strings represent text, so leave it that way:
title = metadata['xesam:title']
Similar for artist assignment, but get the first element of the iterable:
artist = metadata['xesam:artist'][0]
Next, in your song-updating logic, use io.open to open the files with a UTF-8 encoding. This lets Unicode strings (text) be written directly and the file will handle the encoding. Also use a with statement to automatically close the file when the with ends.
Program with recommended changes:
import time
import dbus
import io
session_bus = dbus.SessionBus()
spotify_bus = session_bus.get_object("org.mpris.MediaPlayer2.spotify", "/org/mpris/MediaPlayer2")
spotify_properties = dbus.Interface(spotify_bus, "org.freedesktop.DBus.Properties")
def currentplaying():
metadata = spotify_properties.Get("org.mpris.MediaPlayer2.Player", "Metadata")
title = metadata['xesam:title']
artist = metadata['xesam:artist'][0]
playing = artist + " - " + title + " "
return playing
while True:
with io.open('currentsongspotify.txt', encoding='utf8') as filetxt:
oldtitle = filetxt.read()
newtitle = currentplaying()
if newtitle == oldtitle:
time.sleep(1)
else:
with io.open('currentsongspotify.txt','w',encoding='utf8') as filetxt: # save newtitle to file, overwriting existing data
filetxt.write(newtitle)
print 'new file saved:',newtitle

The error you getting is not about unicode, it is about wrong type. Python complains that you trying to call string method encode from the array object. Which does not have this method.
The first this I would try is to remove redundant brackets here it getting artiststr like this: artiststr = str(metadata['xesam:artist']).
But I'm not sure this would work. If it doesn't work, you need to find out what type has metadata['xesam:artist']. Looks like it is not string, but array. So you need to fix the code which fills metadata['xesam:artist'] with data. You can try to use debugger or just print() function to find out the content of metadata['xesam:artist']. Or provide the relevant code in you question too.

Final program, feel free to use if you like:
import time
import dbus
session_bus = dbus.SessionBus()
spotify_bus = session_bus.get_object("org.mpris.MediaPlayer2.spotify", "/org/mpris/MediaPlayer2")
spotify_properties = dbus.Interface(spotify_bus, "org.freedesktop.DBus.Properties")
def currentplaying():
metadata = spotify_properties.Get("org.mpris.MediaPlayer2.Player", "Metadata")
title = str((metadata['xesam:title']).encode('utf-8'))
artiststr = str((metadata['xesam:artist'])[0].encode('utf-8'))
artist = artiststr
playing = (artist + " - " + title + " ")
return playing
while True:
filetxt = open("/home/USER/Desktop/currentsongspotify.txt", "r")
oldtitle = filetxt.read()
filetxt.close()
newtitle = str(currentplaying())
if(newtitle == oldtitle):
time.sleep(1)
else:
filetxt = open("/home/USER/Desktop/currentsongspotify.txt", "w") #save newtitle to file, overwriting existing data
filetxt.write(str(newtitle))
print("new file saved: " + newtitle)