[python] filename and line number of Python script

How can I get the file name and line number in a Python script?

Exactly the file information we get from an exception traceback. In this case without raising an exception.

Whether you use currentframe().f_back depends on whether you are using a function or not.

Calling inspect directly:

from inspect import currentframe, getframeinfo

cf = currentframe()
filename = getframeinfo(cf).filename

print "This is line 5, python says line ", cf.f_lineno 
print "The filename is ", filename

Calling a function that does it for you:

from inspect import currentframe

def get_linenumber():
    cf = currentframe()
    return cf.f_back.f_lineno

print "This is line 7, python says line ", get_linenumber()

import inspect    

file_name = __FILE__
current_line_no = inspect.stack()[0][2]
current_function_name = inspect.stack()[0][3]

#Try printing inspect.stack() you can see current stack and pick whatever you want 

Here's what works for me to get the line number in Python 3.7.3 in VSCode 1.39.2 (dmsg is my mnemonic for debug message):

import inspect

def dmsg(text_s):
    print (str(inspect.currentframe().f_back.f_lineno) + '| ' + text_s)

To call showing a variable name_s and its value:

name_s = put_code_here
dmsg('name_s: ' + name_s)

Output looks like this:

37| name_s: value_of_variable_at_line_37

Better to use sys also-

print dir(sys._getframe())
print dir(sys._getframe().f_lineno)
print sys._getframe().f_lineno

The output is:

['__class__', '__delattr__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'f_back', 'f_builtins', 'f_code', 'f_exc_traceback', 'f_exc_type', 'f_exc_value', 'f_globals', 'f_lasti', 'f_lineno', 'f_locals', 'f_restricted', 'f_trace']
['__abs__', '__add__', '__and__', '__class__', '__cmp__', '__coerce__', '__delattr__', '__div__', '__divmod__', '__doc__', '__float__', '__floordiv__', '__format__', '__getattribute__', '__getnewargs__', '__hash__', '__hex__', '__index__', '__init__', '__int__', '__invert__', '__long__', '__lshift__', '__mod__', '__mul__', '__neg__', '__new__', '__nonzero__', '__oct__', '__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdiv__', '__rdivmod__', '__reduce__', '__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmod__', '__rmul__', '__ror__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__', '__rtruediv__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__truediv__', '__trunc__', '__xor__', 'bit_length', 'conjugate', 'denominator', 'imag', 'numerator', 'real']
14

Filename:

__file__
# or
sys.argv[0]

Line:

inspect.currentframe().f_lineno

(not inspect.currentframe().f_back.f_lineno as mentioned above)

In Python 3 you can use a variation on:

def Deb(msg = None):
  print(f"Debug {sys._getframe().f_back.f_lineno}: {msg if msg is not None else ''}")

In code, you can then use:

Deb("Some useful information")
Deb()

To produce:

123: Some useful information
124:

Where the 123 and 124 are the lines that the calls are made from.

Handy if used in a common file - prints file name, line number and function of the caller:

import inspect
def getLineInfo():
    print(inspect.stack()[1][1],":",inspect.stack()[1][2],":",
          inspect.stack()[1][3])

Just to contribute,

there is a linecache module in python, here is two links that can help.

linecache module documentation
linecache source code

In a sense, you can "dump" a whole file into its cache , and read it with linecache.cache data from class.

import linecache as allLines
## have in mind that fileName in linecache behaves as any other open statement, you will need a path to a file if file is not in the same directory as script
linesList = allLines.updatechache( fileName ,None)
for i,x in enumerate(lineslist): print(i,x) #prints the line number and content
#or for more info
print(line.cache)
#or you need a specific line
specLine = allLines.getline(fileName,numbOfLine)
#returns a textual line from that number of line

For additional info, for error handling, you can simply use

from sys import exc_info
try:
     raise YourError # or some other error
except Exception:
     print(exc_info() )

Thanks to mcandre, the answer is:

#python3
from inspect import currentframe, getframeinfo

frameinfo = getframeinfo(currentframe())

print(frameinfo.filename, frameinfo.lineno)