How can I escape latex code received through user input

Question

I read in a string from a GUI textbox entered by the user and process it through pandoc  The string contains latex directives for math which have backslash characters  I want to send in the string as a raw string to pandoc for processing  But something like   theta  becomes a tab and  heta    How can I convert a string literal that contains backslash characters to a raw string      Edit    Thanks develerx  flying sheep and unutbu  But none of the solutions seem to help me  The reason is that there are other backslashed-characters which do not have any effect in python but do have a meaning in latex    For example   lambda   All the methods suggested produce     lambda   which does not go through in latex processing -- it should remain as  lambda   Another edit   If i can get this work  i think i should be through   Mark  All three methods give answers that i dont desire   a   nu    lambda    theta    b a replace r     r          c   r   a   d a encode  string escape    print a  u    lambda     heta print b  u    lambda     heta print c   nu     lambda    theta  print d  nu     lambda    theta

User · Accepted Answer

Python   s raw strings are just a way to tell the Python interpreter that it should interpret backslashes as literal slashes  If you read strings entered by the user  they are already past the point where they could have been raw  Also  user input is most likely read in literally  i e     raw      This means the interpreting happens somewhere else  But if you know that it happens  why not escape the backslashes for whatever is interpreting it   s   s replace                  Note that you can t do r    as    a raw string cannot end in a single backslash     but I could have used r     as well for the second argument    If that doesn   t work  your user input is for some arcane reason interpreting the backslashes  so you   ll need a way to tell it to stop that

User · Answer

a   nu    lambda    theta  d a encode  string escape   replace              print d     nu    lambda    theta   This shows that there is a single backslash before the n  l and t   print list d             n    u                         l    a    m    b    d    a                         t    h    e    t    a       There is something funky going on with your GUI  Here is a simple example of grabbing some user input through a Tkinter Entry  Notice that the text retrieved only has a single backslash before the n  l  and t  Thus no extra processing should be necessary   import Tkinter as tk  def callback        print list text get      root   tk Tk   root config    b   tk Button root  text  get   width 10  command callback   text tk StringVar    entry   tk Entry root textvariable text  b pack padx 5  pady 5  entry pack padx 5  pady 5  root mainloop     If you type  nu    lambda    theta into the Entry box  the console will  correctly  print           n    u                         l    a    m    b    d    a                         t    h    e    t    a     If your GUI is not returning similar results  as your post seems to suggest   then I d recommend looking into fixing the GUI problem  rather than mucking around with string escape and string replace

User · Answer

When you read the string from the GUI control  it is already a  raw  string  If you print out the string you might see the backslashes doubled up  but that s an artifact of how Python displays strings  internally there s still only a single backslash    gt  gt  gt  a   nu    lambda    theta   gt  gt  gt  a   nu     lambda    theta   gt  gt  gt  len a  20  gt  gt  gt  b r  nu    lambda    theta   gt  gt  gt  b    nu     lambda     theta   gt  gt  gt  len b  22  gt  gt  gt  b 0        gt  gt  gt  print b  nu    lambda    theta

User · Answer

If you want to convert an existing string to raw string  then we can reassign that like below  s1    welcome tto tPython  raw s1     r  s1 print raw s1    Will print  welcome tto tPython

User · Answer

I spent a lot of time trying different answers all around the internet  and I suspect the reasons why one thing works for some people and not for others is due to very small weird differences in application  For context  I needed to read in file names from a csv file that had strange and or unmappable unicode characters and write them to a new csv file  For what it s worth  here s what worked for me   s     u00e7 u00a3 u0085 u00e5 u008d u0095    csv freaks if you try to write this s   repr s encode  utf-8    ignore    2 -1

[python] How can I escape latex code received through user input?

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