How can I concatenate a string and a number in Python?

I was trying to concatenate a string and a number in Python. It gave me an error when I tried this:

"abc" + 9

The error is:

Traceback (most recent call last):
  File "<pyshell#5>", line 1, in <module>
    "abc" + 9
TypeError: cannot concatenate 'str' and 'int' objects

Why am I not able to do this?

How can I concatenate a string and a number in Python?

Python is strongly typed. There are no implicit type conversions.

You have to do one of these:

"asd%d" % 9
"asd" + str(9)

If it worked the way you expected it to (resulting in "abc9"), what would "9" + 9 deliver? 18 or "99"?

To remove this ambiguity, you are required to make explicit what you want to convert in this case:

"abc" + str(9)

Since Python is a strongly typed language, concatenating a string and an integer, as you may do in Perl, makes no sense, because there's no defined way to "add" strings and numbers to each other.

> Explicit is better than implicit.

...says "The Zen of Python", so you have to concatenate two string objects. You can do this by creating a string from the integer using the built-in str() function:

>>> "abc" + str(9)
'abc9'

Alternatively, use Python's string formatting operations:

>>> 'abc%d' % 9
'abc9'

Perhaps better still, use str.format():

>>> 'abc{0}'.format(9)
'abc9'

The Zen also says:

> There should be one-- and preferably only one --obvious way to do it.

Which is why I've given three options.

Either something like this:

"abc" + str(9)

or

"abs{0}".format(9)

or

"abs%d" % (9,)

You have to convert the int into a string:

"abc" + str(9)

You would have to convert the int into a string.

# This program calculates a workers gross pay

hours = float(raw_input("Enter hours worked: \n"))

rate = float(raw_input("Enter your hourly rate of pay: \n"))

gross = hours * rate

print "Your gross pay for working " +str(hours)+ " at a rate of " + str(rate) + " hourly is $"  + str(gross)

Do it like this:

"abc%s" % 9
#or
"abc" + str(9)