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Python Commandments

Python string join method

The join() function is a string operation function, which also operates on a string. It combines the strings written between the parameters.

key="\t".join(('a','b','c'))
result= key.split("\t")
print(result)
print(result[0])
print(result[1])

The join function connects the specified characters within ().

",".join ("a", "b", "c") results in an error because it must be an object in parentheses. If there are more than one, program the tuple, or list.

Python join() examples

example 1

Combine a string with different delimiters. The string is split by character and the delimiter is inserted:

>>> a="abcd"
>>> ",".join(a)
'a,b,c,d'
>>> "|".join(['a','b','c'])
'a|b|c'
>>> ",".join(('a','b','c'))
'a,b,c'
>>> ",".join({'a':1,'b':2,'c':3})
'a,c,b'

example 2

If the tuple is not used, it will be separated by each character, A, B will also be separated internally.

>>> k1="ttt"
>>> k2="ss"
>>> a=k1+k2
>>> ",".join(a)
't,t,t,s,s,s'
python string join() method

example 3

You can combine strings using the + operator, in fact that works on any sequence like lists or tuples.

li = ['hello','python20','!']
str1 = li[0]+' '+ li[1]+' '+li[2]
print(str1)

Result:

hello python20 !

But Python provides the join() method, which allows the string to be combined. That is a lot shorter to write.

The following is done with join().

li = ['hello','python20','!']
print(' '.join(li))

Result:

hello python20 !