Is it possible to use a try except block inside of a lambda function? I need the lambda function to convert a certain variable into an integer, but not all of the values will be able to be converted into integers.
Nope. A Python lambda can only be a single expression. Use a named function.
It is convenient to write a generic function for converting types:
def tryconvert(value, default, *types):
for t in types:
try:
return t(value)
except (ValueError, TypeError):
continue
return default
Then you can write your lambda:
lambda v: tryconvert(v, 0, int)
You could also write tryconvert()
so it returns a function that takes the value to be converted; then you don't need the lambda:
def tryconvert(default, *types):
def convert(value):
for t in types:
try:
return t(value)
except (ValueError, TypeError):
continue
return default
# set name of conversion function to something more useful
namext = ("_%s_" % default) + "_".join(t.__name__ for t in types)
if hasattr(convert, "__qualname__"): convert.__qualname__ += namext
convert.__name__ += namext
return convert
Now tryconvert(0, int)
returns a function convert_0_int
that takes a value and converts it to an integer, and returns 0
if this can't be done. You can use this function right away (not saving a copy):
mynumber = tryconert(0, int)(value)
Or save it to call it later:
intconvert = tryconvert(0, int)
# later...
mynumber = intconvert(value)