6.9. Splitting and Joining Strings

Two of the most useful methods on strings involve lists of strings. The split method breaks a string into a list of words. By default, any number of whitespace characters is considered a word boundary.

song = "The rain in Spain..." wds = song.split() print(wds)

An optional argument called a delimiter can be used to specify which characters to use as word boundaries.

The following example uses the string ai as the delimiter:

song = "The rain in Spain..." wds = song.split('ai') print(wds)

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Notice that the delimiter doesn’t appear in the result.

The inverse of the split method is join. You choose a desired separator string, (often called the glue) and join the list with the glue between each of the elements.

wds = ["red", "blue", "green"] glue = ';' s = glue.join(wds) print(s) print(wds) print("***".join(wds)) print("".join(wds))

The list that you glue together (wds in this example) is not modified. Also, you can use empty glue or multi-character strings as glue.

Check your understanding

Create a new list of the 6th through 13th elements of lst (eight items in all) and assign it to the variable output.

lst = ["swimming", 2, "water bottle", 44, "lollipop", "shine", "marsh", "winter", "donkey", "rain", ["Rio", "Beijing", "London"], [1,2,3], "gold", "bronze", "silver", "mathematician", "scientist", "actor", "actress", "win", "cell phone", "leg", "running", "horse", "socket", "plug", ["Phelps", "le Clos", "Lochte"], "drink", 22, "happyfeet", "penguins"] ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testFour(self): self.assertEqual(output, lst[5:13], "Testing that output value is assigned to correct value.") myTests().main()

Create a variable output and assign to it a list whose elements are the words in the string str1.

str1 = "OH THE PLACES YOU'LL GO" ==== from unittest.gui import TestCaseGui class myTests(TestCaseGui): def testSix(self): self.assertEqual(output, ["OH", "THE", "PLACES", "YOU'LL", "GO"], "Testing that output value is assigned to correct value.") myTests().main()

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