Python3 Programming #post_9 ### Python - Slicing Strings #### Slicing In Python, slicing allows you to extract a specific portion of a string by defining a range of indices. You can use the slice syntax, which involves specifying a start and end index, separated by a colon (:), to return part of the string. ##### Example: To get the characters from position 2 to position 5 (excluding 5): b = "Hello, World!" print(b[2:5]) # Output: "llo" Note: The first character has an index of 0. --- #### Slice From the Start If you leave out the start index, slicing will begin from the very first character in the string. ##### Example: To get the characters from the start up to position 5 (excluding 5): b = "Hello, World!" print(b[:5]) # Output: "Hello" --- #### Slice to the End If you leave out the end index, the slicing will continue to the end of the string. ##### Example: To get the characters from position 2 to the end: b = "Hello, World!" print(b[2:]) # Output: "llo, World!" --- #### Negative Indexing You can also use negative indexing to slice a string from the end. Negative indices count backward from the end of the string. ##### Example: Get the characters from position -5 to -2 (excluding -2): b = "Hello, World!" print(b[-5:-2]) # Output: "orl" --- #### Exercise: What will be the result of the following code? x = 'Welcome' print(x[3:5]) Options: - lcome - come - com - co --- ### Python - Modify Strings Python offers several built-in methods to modify strings. Let’s explore some of the most commonly used methods: #### Upper Case The upper() method converts all the characters in a string to uppercase. ##### Example: a = "Hello, World!" print(a.upper()) # Output: "HELLO, WORLD!" --- #### Lower Case The lower() method converts all the characters in a string to lowercase. ##### Example: a = "Hello, World!" print(a.lower()) # Output: "hello, world!" --- #### Remove Whitespace The strip() method removes any leading and trailing whitespace (spaces before and after the text). ##### Example: a = " Hello, World! " print(a.strip()) # Output: "Hello, World!" --- #### Replace String The replace() method replaces a part of the string with another string. ##### Example: a = "Hello, World!" print(a.replace("H", "J")) # Output: "Jello, World!" --- #### Split String The split() method splits a string into a list of substrings based on a specified separator (in this case, a comma). ##### Example: a = "Hello, World!" print(a.split(",")) # Output: ['Hello', ' World!'] --- ### Python - String Concatenation #### String Concatenation To concatenate (or combine) two strings, you can use the + operator. ##### Example: Merge variables a and b into variable c: a = "Hello" b = "World" c = a + b print(c) # Output: "HelloWorld" ##### Example: To add a space between a and b, include a space in between: a = "Hello" b = "World" c = a + " " + b print(c) # Output: "Hello World" --- #### Exercise: What is the correct syntax to merge variables x and y into z? - z = x, y - z = x = y - z = x + y --- ### النسخة العربية: Python - تقطيع النصوص #### التقطيع في بايثون، يمكنك استخدام التقطيع لاستخراج جزء محدد من النص عن طريق تحديد نطاق من الفهارس. يمكنك استخدام صيغة التقطيع، والتي تتضمن تحديد فهرس البداية وفهرس النهاية مفصولين بنقطتين (:) لإرجاع جزء من النص. ##### مثال: لإرجاع الأحرف من الفهرس 2 إلى 5 (غير شامل): b = "Hello, World!" print(b[2:5]) # النتيجة: "llo" ملحوظة: أول حرف في النص يحتوي على الفهرس 0. --- #### التقطيع من البداية إذا لم تحدد فهرس البداية**، فسيبدأ التقطيع من أول حرف في النص. ##### مثال: لإرجاع الأحرف من البداية حتى الفهرس 5 (غير شامل): b = "Hello, World!" print(b[:5]) # النتيجة: "Hello" --- #### التقطيع إلى النهاية إذا لم تحدد فهرس النهاية، فسيستمر التقطيع حتى نهاية النص. ##### مثال: لإرجاع الأحرف من الفهرس 2 حتى النهاية: b = "Hello, World!" print(b[2:]) # النتيجة: "llo, World!" ---