{"id":359,"date":"2023-06-20T21:21:55","date_gmt":"2023-06-20T21:21:55","guid":{"rendered":"https:\/\/learnlearn.uk\/edexcel-igcse-computer-science\/?page_id=359"},"modified":"2023-06-20T21:27:41","modified_gmt":"2023-06-20T21:27:41","slug":"python-string-methods-manipulation","status":"publish","type":"page","link":"https:\/\/learnlearn.uk\/edexcel-igcse-computer-science\/python-string-methods-manipulation\/","title":{"rendered":"Python String Methods & Manipulation"},"content":{"rendered":"
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Concatenation<\/h2>\n
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String Concatenation<\/h3>\n

In Python, you can concatenate strings using the +<\/code> operator or by using the str.join()<\/code> method. Here are examples of both methods:<\/p>\n

Method – Using the +<\/code> operator<\/strong><\/p>\n

<\/p>\n

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str1 =<\/span> \"Hello\"<\/span>\r\nstr2 =<\/span> \"World\"<\/span>\r\nresult =<\/span> str1 +<\/span> \" \"<\/span> +<\/span> str2\r\nprint<\/span>(result)  # Output: Hello World<\/span>\r\n<\/pre>\n<\/div>\n
Method 2 – Using the str.join()<\/code> method<\/strong><\/p>\n
<\/p>\n
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str1 =<\/span> \"Hello\"<\/span>\r\nstr2 =<\/span> \"World\"<\/span>\r\nresult =<\/span> \" \"<\/span>.<\/span>join([str1, str2])\r\nprint<\/span>(result)  # Output: Hello World<\/span>\r\n<\/pre>\n<\/div>\n
Method 3 – Using f-strings (formatted string literals)<\/strong><\/p>\n
If you want to join multiples or mixed data types (like strings and integer) then f-strings are usually the easiest option. Otherwise you will need to use type casting with mystr = str(myint).<\/p>\n
<\/p>\n
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name =<\/span> \"Alice\"<\/span>\r\nage =<\/span> 25<\/span>\r\nheight =<\/span> 1.65<\/span>\r\nmessage =<\/span> f\"My name is {name}, I am {age} years old, and my height is {height} meters.\"<\/span>\r\n\r\nprint<\/span>(message)  # Output: My name is Alice, I am 25 years old, and my height is 1.65 meters.<\/span>\r\n<\/pre>\n<\/div>\n\n<\/div>
Slicing<\/h2>\n
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String Slicing<\/h3>\n
\"\"<\/p>\n
In Python, string slicing allows you to extract a portion of a string by specifying a start and end index. The basic syntax for string slicing is string[start:end]<\/code>.<\/p>\n
Example<\/strong>
\n<\/p>\n
\n
text =<\/span> \"helloworld\"<\/span>\r\n\r\n# Extracting a substring from index 3 to 7 (excluding index 7)<\/span>\r\nsubstring1 =<\/span> text[3<\/span>:7<\/span>]\r\nprint<\/span>(substring1)  # Output: lowo<\/span>\r\n\r\n# Extracting a substring from index -5 to the end<\/span>\r\nsubstring2 =<\/span> text[-<\/span>5<\/span>:]\r\nprint<\/span>(substring2)  # Output: world<\/span>\r\n\r\n# Extracting a substring from index 0 to the end with a step of 2<\/span>\r\nsubstring3 =<\/span> text[0<\/span>::2<\/span>]\r\nprint<\/span>(substring3)  # Output: hlool<\/span>\r\n\r\n# Reversing the string<\/span>\r\nreversed_text =<\/span> text[::-<\/span>1<\/span>]\r\nprint<\/span>(reversed_text)  # Output: dlrowolleh<\/span>\r\n<\/pre>\n<\/div>\n\n<\/div>
Negative Indexing<\/h2>\n
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Negative indexing<\/h3>\n
Negative indexing allows you to slice a string starting from the end of the string.<\/p>\n
\"\"<\/p>\n
<\/p>\n
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text =<\/span> \"helloworld\"<\/span>\r\n\r\n# Extracting a substring starting from the second last character to the end<\/span>\r\nsubstring1 =<\/span> text[-<\/span>2<\/span>:]\r\nprint<\/span>(substring1)  # Output: ld<\/span>\r\n\r\n# Extracting a substring starting from the third last character to the fifth last character (excluding index -5)<\/span>\r\nsubstring2 =<\/span> text[-<\/span>3<\/span>:-<\/span>5<\/span>]\r\nprint<\/span>(substring2)  # Output: <\/span>\r\n\r\n# Extracting a substring starting from the beginning to the fourth last character<\/span>\r\nsubstring3 =<\/span> text[:-<\/span>4<\/span>]\r\nprint<\/span>(substring3)  # Output: hellowo<\/span>\r\n\r\n# Reversing the string using negative step value<\/span>\r\nreversed_text =<\/span> text[::-<\/span>1<\/span>]\r\nprint<\/span>(reversed_text)  # Output: dlrowolleh<\/span>\r\n<\/pre>\n<\/div>\n\n<\/div>
Methods<\/h2>\n
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String Methods<\/h3>\n
Python provides several built-in string methods that you can use to perform various operations and manipulations on strings.<\/p>\n