Python String join() Method

join() is an inbuilt string function in Python used to join elements of the sequence separated by a string separator. This function joins elements of a sequence and makes it a string. 

Syntax:

string_name.join(iterable) 

Parameters:

string_name- It can be any string, character, digit or special character. 

The join() method takes iterable – objects capable of returning their members one at a time. Some examples are List, Tuple, String, Dictionary, and Set

Return Value:

The join() method returns a string concatenated with the elements of iterable. 

Type Error:

If the iterable contains any non-string values, it raises a TypeError exception. 

Example 1: Working of join() method

Python

# Python program to demonstrate the
# use of join function to join list
# elements with a character.

list1 = ['1','2','3','4']

s = "-"

# joins elements of list1 by '-'
# and stores in string s
s = s.join(list1)

# join use to join a list of
# strings to a separator s
print(s)

Output: 

1-2-3-4

Example 2: Joining with an empty string

Python

# Python program to demonstrate the
# use of join function to join list
# elements without any separator.

# Joining with empty separator
list1 = ['g','e','e','k', 's']
print("".join(list1))

Output: 

geeks

Example 3: Joining String with multiple parameters

Python3

#Joining string character to string
'S'.join('12345')
#Joining special symbols with string
'()'.join('12345')
#Joining digits with string
'100'.join('Geeks')
#Joining special character with dictionary
'_'.join({'Geek':1,'For':2,'Geeks':3})

Output:

'1S2S3S4S5'
'1()2()3()4()5'
'G100e100e100k100s'
'Geek_For_Geeks'

Note: When joining a string with a dictionary,  it will join with the keys of a dictionary, not with values.