Python String and Integer concatenation

Question

I want to create string using integer appended to it, in a for loop. Like this:

for i in range(1,11):
  string="string"+i

But it returns an error:

TypeError: unsupported operand type(s) for +: 'int' and 'str'

What's the best way to concatenate the String and Integer?

Solution 1

NOTE:

The method used in this answer (backticks) is deprecated in later versions of Python 2, and removed in Python 3. Use the str() function instead.

---

You can use :

string = 'string'
for i in range(11):
    string +=`i`
print string

It will print string012345678910.

To get string0, string1 ..... string10 you can use this as @YOU suggested

>>> string = "string"
>>> [string+`i` for i in range(11)]

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Update as per Python3

You can use :

string = 'string'
for i in range(11):
    string +=str(i)
print string

It will print string012345678910.

To get string0, string1 ..... string10 you can use this as @YOU suggested

>>> string = "string"
>>> [string+str(i) for i in range(11)]

Solution 2

for i in range (1,10):
    string="string"+str(i)

To get string0, string1 ..... string10, you could do like

>>> ["string"+str(i) for i in range(11)]
['string0', 'string1', 'string2', 'string3', 'string4', 'string5', 'string6', 'string7', 'string8', 'string9', 'string10']

Solution 3

for i in range[1,10]: 
  string = "string" + str(i)

The str(i) function converts the integer into a string.

Solution 4

string = 'string%d' % (i,)

Solution 5

for i in range(11):
    string = "string{0}".format(i)

What you did (range[1,10]) is

• a TypeError since brackets denote an index (a[3]) or a slice (a[3:5]) of a list,
• a SyntaxError since [1,10] is invalid, and
• a double off-by-one error since range(1,10) is [1, 2, 3, 4, 5, 6, 7, 8, 9], and you seem to want [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

And string = "string" + i is a TypeError since you can't add an integer to a string (unlike JavaScript).

Look at the documentation for Python's new string formatting method, it is very powerful.

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