Error with concatenating list to string in Python

Question

I am trying to pass class element to method. Element is formed dynamically inserting current time in it. Mine class looks something like this:

class MineContact(dict):
    def __init__(self, **kwargs):
        # set your default values
        import time
        curr_time = repr(time.time()).replace('.', '') 
        self['givenName'] = ['name%s' % curr_time[10:]]
        ...

So, I create object of this class and now I want to insert it as method argument:

    contact = MineContact()
    extra_text = "-%d" % (self.iteration)
    new_contact.insert_given_name(contact.givenName + extra_text)

When I run this script, I get this type of error:

TypeError: can only concatenate list (not "str") to list

So, does anyone knows where am I getting it wrong?

Constantinius · Accepted Answer · 2014-05-07 08:09:19Z

3

givenName seems to be a list. You can append another list like this:

new_contact.insert_given_name(contact.givenName + [extra_text])

answered May 7, 2014 at 8:09

Constantinius

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Comments

Xing Fei · Accepted Answer · 2014-05-07 08:10:14Z

-1

contact.givenName is a list, and extra_text is a string. in python you can add string to string, or list to list. you can't add string to list.

if you'd like to add string to a list, use list.append method.

mylist.append(mystr)

answered May 7, 2014 at 8:10

Xing Fei

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4 Comments

Tim Pietzcker Over a year ago

That modifies the existing list which is not what the OP is trying to do.

sshashank124 Over a year ago

Also, that will pass None when passed as a function parameter since list.append(val) returns None

Xing Fei Over a year ago

I am telling him how to concatate list and string. why you think I give him code to copy and paste?

Tim Pietzcker Over a year ago

Your approach is fundamentally wrong - the code will not work in his use case. The .append() method can be used to append a string to an existing list, not to create a new list from a given list, extended by one element.

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