Empty Parameter for Python Lambda Function

Question

Is it possible in python to write a lambda function that does not need any parameters passed to it? For instance, is there a way to translate this function:

def file_opener():
    f = open('filename.txt').read()
    return f

or any other function with no passed input into a lambda expression?

Answer 1

You certainly can do it..

x = lambda : 6
print(x())  # prints -> 6

You probably shouldn't though. Once you feel the need to bind a function to a variable name you should go the long road instead (def ..) as you do it in your example.

Answer 2

Try this (Recommended as no hard-coding is present):

file = lambda f: open(f).read()

print (file('open.txt'))

If you don't want to pass filename as an argument then use this:

f = lambda: open('open.txt').read()

print (f())