MRAB , Thanks for your solution it looks neat and best !
On Fri, Sep 1, 2017 at 11:14 PM, MRAB <pyt...@mrabarnett.plus.com> wrote: > On 2017-09-01 18:13, Ganesh Pal wrote: > >> In the fixed length string i.e "a0000",last 4 bits i.e "0000" should be >> replaced by the user provided value ( the value is between 0001 + f f f f >> ) >> . I intend to form final_string using a fixed_string and an user >> provided >> user_string >> >> >> Example: >> >> fixed_string = "a0000" >> user_string ='1' >> >> final string = fixed_string and user_string >> >> Example : >> >> "a0000" and "1" => a0001 >> >> "a0000" and "aa" => c00aa >> >> >> PS : "and" this is not logical and it's just for example >> >> If I concatenation using + or += or it's append the value at the end of >> the string >> >> "a0000" + "1" ===> expected was a0001 >>>>> >>>> 'a00001' >> >> >> >> I am on python 2.7 and Linux , any ideas that you recommend to handle >> this >> >> How long is user_string? len(user_string) > Truncate fixed_string by that many characters: fixed_string[ : > -len(user_string)] > > Then append the user_string: fixed_string[ : -len(user_string)] + > user_string > > Example: > > >>> fixed_string = "a0000" > >>> user_string ='1' > >>> len(user_string) > 1 > >>> fixed_string[ : -len(user_string)] > 'a000' > >>> fixed_string[ : -len(user_string)] + user_string > 'a0001' > > Note: this won't work properly if len(user_string) == 0, so if that could > happen, just skip it. (Appending an empty string has no effect anyway!) > -- > https://mail.python.org/mailman/listinfo/python-list > -- https://mail.python.org/mailman/listinfo/python-list
