[] became None after appending

Question

I am fairly new to python. I was trying to store raw input to an empty list. And apparently, the input didn't go into the empty list. Then what went wrong?

Latitude = []
Longitude = []
print Latitude #**THIS GIVES []**

Lat_input = raw_input("What is your latitude:")
Latitude = Latitude.append(Lat_input)
print Latitude # **HERE I GOT NONE**

Long_input = raw_input("WHat is your longitude:")
Longitude = Longitude.append(Long_input)

I looked up some other postings, still didn't figure out what I did wrong. What did I miss? Why is my list gone? Thanks, guys!

possible duplicate of [list append gives None as result](http://stackoverflow.com/questions/26151795/list-append-gives-none-as-result) — Charles Duffy, Oct 11 '14 at 00:13

Charles Duffy · Accepted Answer · 2014-10-10T20:51:45.483

append is an in-place operation; it doesn't return a value.

Just run:

Longitude.append(Long_input)

...not

Longitude = Longitude.append(Long_input)

This is by design and intent: Returning None rather than a value makes it clear that a function is being called for its side effects rather than its return value.

If you didn't want to modify the existing Longitude in place, but instead wanted to create a new list with the new item appended, then you might instead use:

Longitude = Longitude + [Long_input]

[] became None after appending

1 Answers1