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In Python, a string is a sequence of characters.

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A string is contained within two quotes.

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You could also use single quotes.

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A string can be spaces or digits.

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A string can also be special characters.

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We can bind or assign a string to another variable.

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It is helpful to think of a string as an ordered sequence.

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Each element in the sequence can be accessed using

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an index represented by the array of numbers.

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The first index can be accessed as follows:

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We can access index six.

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Moreover, we can access the 13th index.

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We can also use negative indexing with strings.

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The last element is given by the index negative one.

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The first element can be obtained by index negative 15 and so on.

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We can bind a string to another variable.

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It is helpful to think of string as a list or tuple.

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We can treat the string as a sequence and perform sequence operations.

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We can also input a stride value as follows:

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The two indicates we'd select every second variable.

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We can also incorporate slicing.

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In this case, we return every second value up to index four.

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We can use the len command to obtain the length of the string.

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As there are 15 elements, the result is 15.

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We can concatenate or combine strings.

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We use the addition symbols.

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The result is a new string that is a combination of both.

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We can replicate values of a string.

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We simply multiply the string by the number of times we would like to replicate it-

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in this case, three.

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The result is a new string.

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The new string consists of three copies of the original string.

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This means you cannot change the value of the string, but you can create a new string.

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For example, you can create a new string by setting it to

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the original variable and concatenate it with a new string.

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The result is a new string that changes from

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Michael Jackson to Michael Jackson is the best.

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Strings are immutable.

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Back slashes represent the beginning of escape sequences.

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Escape sequences represent strings that may be difficult to input.

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For example, backslashes "n" represent a new line.

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The output is given by a new line after the backslashes "n" is encountered.

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Similarly, backslash "t" represents a tab.

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The output is given by a tab where the backslash, "t" is.

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If you want to place a backslash in your string,

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use a double backslash.

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The result is a backslash after the escape sequence.

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We can also place an "r" in front of the string.

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Now, let's take a look at string methods.

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Strings are sequences and as such,

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have apply methods that work on lists and tuples.

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Strings also have a second set of methods that just work on strings.

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When we apply a method to the string A,

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we get a new string B that is different from A.

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Let's do some examples.

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Let's try with the method "Upper".

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This method converts lowercase characters to uppercase characters.

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In this example, we set the variable A to the following value.

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We apply the method "Upper", and set it equal to B.

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The value for B is similar to A, but all the characters are uppercase.

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The method replaces a segment of the string- i.e.

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a substring with a new string.

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We input the part of the string we would like to change.

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The second argument is what we would like to exchange the segment with.

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The result is a new string with a segment changed.

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The method find, find substrings.

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The argument is the substring you would like to find.

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The output is the first index of the sequence.

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We can find the substring Jack.

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If the substring is not in the string,

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the output is negative one.

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Check the labs for more examples.

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(Music)