Converting a list of strings into a string is a very common operation.<\/p>\n\n\n\n
For example, assume you have a list of words that that look like this:<\/p>\n\n\n\n
words = [\"Messi\", \"is\", \"the\", \"best\", \"soccer\", \"player\"]<\/code><\/pre>\n\n\n\nAnd you want to convert this into the string:<\/p>\n\n\n\n
\"Messi is the best soccer player\"<\/code><\/pre>\n\n\n\nHow can you do that?<\/p>\n\n\n\n
The correct way to achieve this is by using the join<\/span> method.<\/p>\n\n\n\n>>> words = [\"Messi\", \"is\", \"the\", \"best\", \"soccer\", \"player\"]\n>>> sentence = \" \".join(words)\n>>> sentence\n'Messi is the best soccer player'<\/code><\/pre>\n\n\n\nNow that you know the answer, let me explain the join method in more detail.<\/p>\n\n\n\n
The join Method<\/h2>\n\n\n\n
join()<\/span> is a method that is defined on the string class.<\/p>\n\n\n\nThe general syntax of join is as follows:<\/p>\n\n\n\n
str.join(iterable)<\/code><\/pre>\n\n\n\nwhere:<\/p>\n\n\n\n
- str<\/strong> is a string representing the separator<\/em> between the words to be joined.<\/li>
- iterable<\/strong> could be any iterable<\/em> (lists, tuples, string…). This iterable will include all the words to be joined. In this article, I will focus mainly on lists but the same concept applies to tuples, strings, and any iterable for that matter.<\/li><\/ul>\n\n\n\n
Let’s take another example just to make sure everything is clear.<\/p>\n\n\n\n
Say you have a list of strings as follows:<\/p>\n\n\n\n
fruits = [\"apples\", \"bananas\", \"strawberries\"]<\/code><\/pre>\n\n\n\nAnd you would like to convert the list into a single string with all the items in the list separated by a comma<\/em>.<\/p>\n\n\n\nIn this case, the separator is the comma string “, “<\/span> and the iterable is the fruits<\/span> list.<\/p>\n\n\n\n>>> fruits = [\"apples\", \"bananas\", \"strawberries\"]\n>>> csv = \", \".join(fruits)\n>>> csv\n'apples, bananas, strawberries'<\/code><\/pre>\n\n\n\nNote that this only works if you have a list of strings.<\/p>\n\n\n\n
If your list has any item that is not a string, then you will get an error.<\/p>\n\n\n\n
>>> words = [\"Messi\", \"is\", \"number\", 1]\n>>> sentence = \" \".join(words)\nTypeError: sequence item 3: expected str instance, int found<\/code><\/pre>\n\n\n\nSo what do you do in a situation like this?<\/p>\n\n\n\n
Well, if your list has non-string items that could be converted to strings via the built-in str()<\/span> function, then you can use the handy map method to map<\/a> all the items into a string first.<\/p>\n\n\n\n>>> words = [\"Messi\", \"is\", \"number\", 1]\n>>> sentence = \" \".join(map(str, words))\n>>> sentence\n'Messi is number 1'<\/code><\/pre>\n\n\n\nThere you go.<\/p>\n\n\n\n
So next time you want to convert a list of strings into a single string, don’t create your own custom function to do that. Just use the Join method.<\/p>\n\n\n
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