Tuesday, October 27, 2009

Joining Strings










Joining Strings






print "Words:" + word1 + word2 + word3 + word4
print "List: " + ' '.join(wordList)




Strings can be joined together using a simple add operation, formatting the strings together or using the join() method. Using either the + or += operation is the simplest method to implement and start off with. The two strings are simply appended to each other.


Formatting strings together is accomplished by defining a new string with string format codes, %s, and then adding additional strings as parameters to fill in each string format code. This can be extremely useful, especially when the strings need to be joined in a complex format.


The fastest way to join a list of strings is to use the join(wordList) method to join all the strings in a list. Each string, starting with the first, is added to the existing string in order. The join method can be a little tricky at first because it essentially performs a string+=list[x] operation on each iteration through the list of strings. This results in the string being appended as a prefix to each item in the list. This actually becomes extremely useful if you want to add spaces between the words in the list because you simply define a string as a single space and then implement the join method from that string:


word1 = "A"
word2 = "few"
word3 = "good"
word4 = "words"
wordList = ["A", "few", "more", "good", "words"]

#simple Join
print "Words:" + word1 + word2 + word3 + word4
print "List: " + ' '.join(wordList)

#Formatted String
sentence = ("First: %s %s %s %s." %
(word1,word2,word3,word4))
print sentence

#Joining a list of words
sentence = "Second:"
for word in wordList:
sentence += " " + word
sentence += "."
print sentence


join_str.py


Words:Afewgoodwords
List: A few more good words
First: A few good words.
Second: A few more good words.


Output from join_str.py code












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