Python: Convert List into String

The method keyword is similar like in JavaScript. Both are using the join keyword. But in Python, the syntax is reversed (or not, depends on your perspective).

In JavaScript

theArrayVariable.join("thePunctuation")

For example:

var myArray = [1, 2, 3, 4, "tro", "lo", "lo"]; console.log(myArray.join(" ")); // console output will yield: "1 2 3 4 tro lo lo" (string)

In the example above, the array input is converted into strings output with one horizontal white space as the "punctuation" (separator).

---

In Python

"thePunctuation".join(theListVariable)

For example:

myList = ["dark", "wing", "duck"] myString = " ".join(myList) # myString variable consists of: "dark wing duck"

In the example above, the list input is converted into strings output also with one horizontal white space as the "punctuation" (separator).

Unlike in JavaScript, which we can convert an array with mixed types of elements (nonuniform) to string, the join() method in Python only works for list which consists of only string (such as the example above).

To join those mixed element types, first we need to convert each element into string using str() method. Then we can join() them. Let's see an example below.

---

Converting list with mixed types of elements to string

Let's use and expand the JavaScript example input:

myOtherList = [1, 2, 3, 4, "tro", "lo", "lo", [7, 8, 9], {"i_am": "dictionary"}] # myOtherList has integer, string, another list (array), and dictionary (object) myOtherString = " ".join(str(elm) for elm in myOtherList) # Python power # myOtherString has: # "1 2 3 4 tro lo lo [7, 8, 9] {'i_am': 'dictionary'}" (string)

So the iteration shorthand for converting each list element into string is this marked part:

" ".join(str(elm) for elm in myOtherList)

The method above won't change the original list.

For no reason, we can also separate the iteration and conversion, then make a function for it. Let's name the function as convertToString. Here it goes:

def convertToString(a, s): la = len(a) b = a[0:la] # copy list (like slice() in JavaScript) — "buffer" for i in xrange(0, la): # iterate b[i] = str(b[i]) # convert each to string return s.join(b) # return all string myOtherList = [1, 2, 3, 4, "tro", "lo", "lo", [7, 8, 9], {"i_am": "dictionary"}] myAnotherOtherString = convertToString(myOtherList, " ") # myAnotherOtherString also has: # "1 2 3 4 tro lo lo [7, 8, 9] {'i_am': 'dictionary'}" (string)

This method also won't change the original list. As you can see, there's that "buffer" variable.
Very "exploration" *clap clap clap

---

Copy List

This is a neat reference of various methods and shorthand to copy a list in Python (slice an array - in JavaScript) on StackOverflow