I am trying to set a variable equal to the last 6 characters in a line of an input file. Using the below code I am trying to do this but I don't know the syntax to do so, and I get a syntax error. Thanks.
for line in f:
x = line[......$]
Here is the specific error:
File "bettercollapse.py", line 15
x = line[......$]
^
SyntaxError: invalid syntax
You can do that by slicing as
for line in f:
x = line[-6:]
The negative indexing accesses the nth (here 6th) element from the end of the string.
The column is followed by nothing, which means that it continues till the end of the string.
That is here it takes elements from -6 to end of string, the last 6 elements.
Example
>>> string = "asdfasdfqwerqwerqwer"
>>> string[-6:]
'erqwer'
Note
It do count the \n that may be in the file. So for safety the for loop can be written as
>>> with open('test', 'r') as input_file:
... for line in input_file:
... print line[-7:-1]
...
erqwer
>>>
where as the older version would be
>>> with open('test', 'r') as input_file:
... for line in input_file:
... print line[-6:]
...
rqwer
Regexps aren't the right tool for this; slicing is.
for line in f:
print(line[-6:]) # print last 6 characters of line
