Podcast
Questions and Answers
Which method can be used to obtain the length of a string in Java?
Which method can be used to obtain the length of a string in Java?
- .charAt()
- .equals()
- .length() (correct)
- .concat()
Strings in Java can be modified once they are created.
Strings in Java can be modified once they are created.
False (B)
What is the purpose of the .equalsIgnoreCase() method?
What is the purpose of the .equalsIgnoreCase() method?
It compares two strings for equality while ignoring case differences.
The method used to check if a string starts with a specific prefix is called ______.
The method used to check if a string starts with a specific prefix is called ______.
Match the following methods to their function:
Match the following methods to their function:
What is the output of the expression 'Computer Science'.length()?
What is the output of the expression 'Computer Science'.length()?
The .equals() method in Java is case-insensitive.
The .equals() method in Java is case-insensitive.
Provide an example of how to concatenate two strings in Java.
Provide an example of how to concatenate two strings in Java.
To compare two strings for equality, you can use the ______ method.
To compare two strings for equality, you can use the ______ method.
Which method will return the character at index 3 from the string 'Hello'?
Which method will return the character at index 3 from the string 'Hello'?
What will be the output of the following code snippet: System.out.println(string1.startsWith("he")); if string1 is set to "Hello"?
What will be the output of the following code snippet: System.out.println(string1.startsWith("he")); if string1 is set to "Hello"?
The endsWith() method checks if a string starts with a specified prefix.
The endsWith() method checks if a string starts with a specified prefix.
What does the toUpperCase() method do to a string?
What does the toUpperCase() method do to a string?
The __________ method removes whitespace from the beginning and end of a string.
The __________ method removes whitespace from the beginning and end of a string.
What will be the output of the code: System.out.println(string1.indexOf("abc")); if string1 is set to "hello world!"?
What will be the output of the code: System.out.println(string1.indexOf("abc")); if string1 is set to "hello world!"?
The concat() method combines two strings into one string.
The concat() method combines two strings into one string.
What will the following code output? System.out.println(string1.toLowerCase()); if string1 is initialized with "heLLo World!".
What will the following code output? System.out.println(string1.toLowerCase()); if string1 is initialized with "heLLo World!".
Match the following string methods with their descriptions:
Match the following string methods with their descriptions:
What output will you see if you run this code: System.out.println(string1.endsWith("lo")); for string1 set to "Hello"?
What output will you see if you run this code: System.out.println(string1.endsWith("lo")); for string1 set to "Hello"?
To combine two strings, you can use the __________ method in Java.
To combine two strings, you can use the __________ method in Java.
Flashcards
startsWith()
startsWith()
Determines if a string begins with a specified prefix, case-sensitive.
endsWith()
endsWith()
Determines if a string ends with a specified suffix, case-sensitive.
toUpperCase()
toUpperCase()
Converts all characters in a string to uppercase.
toLowerCase()
toLowerCase()
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trim()
trim()
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indexOf()
indexOf()
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concat()
concat()
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What is a Java String?
What is a Java String?
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Immutability of Strings
Immutability of Strings
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Creating a Java String
Creating a Java String
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String Concatenation
String Concatenation
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String Methods
String Methods
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String.length()
String.length()
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String.charAt()
String.charAt()
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String.equals()
String.equals()
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String.equalsIgnoreCase()
String.equalsIgnoreCase()
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String.startsWith()
String.startsWith()
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Study Notes
Java String Overview
- A string is a sequence of characters treated as a single unit, like "Hello World"
- Strings can include letters, digits, and other characters
- Strings are immutable; once created, they cannot be changed. String methods do not modify the original string, instead they return a new string.
Creating a String
- Typical string creation involves using string literals (characters enclosed in double quotes) and assigning them to a variable.
- Syntax:
String variableName = "String"; - Example:
String firstName = "Pedro";String course = "Computer Science";String age = "22";
String Concatenation
- Combining multiple strings:
String fullName = firstName + " " + lastName;orString newString = firstName.concat(" ").concat(lastName);
String Methods
-
Built-in functions for manipulating strings.
-
.length(): Returns the length of the string
- Example:
System.out.println(course.length());(outputs: Length of the string)
- Example:
-
.charAt(): Returns the character at a specific index (position) in the string
- Example:
System.out.println(course.charAt(5));(outputs: Character at position 5)
- Example:
-
.equals(): Compares strings, returning
trueif they are the same (case-sensitive).- Example:
System.out.println(string1.equals(string1));(outputs: true)
- Example:
-
.equalsIgnoreCase(): Compares strings, returning
trueif they are the same ignoring case- Example:
System.out.println(string1.equalsIgnoreCase(string2));(outputs: true, where string2 is lowercase equivalent to string1)
- Example:
-
.startsWith(): Checks if a string starts with a specified prefix
- Example:
System.out.println(string1.startsWith("He"));(outputs: true, if string1 starts with "He")
- Example:
-
.endsWith(): Checks if a string ends with a specified suffix
- Example:
System.out.println(string1.endsWith("lo"));(outputs: true, if string1 ends with "lo")
- Example:
-
.toUpperCase(): Converts all characters to uppercase
-
Example:
System.out.println(string1.toUpperCase());(outputs: HELLO WORLD!) -
.toLowerCase(): Converts all characters to lowercase
- Example:
System.out.println(string1.toLowerCase());(outputs hello world!)
- Example:
-
.trim(): Removes whitespace from the beginning and end of a string
- Example:
System.out.println(string1.trim());(outputs string without leading/trailing whitespace)
- Example:
-
.concat(): Appends one string to another
- Example:
System.out.println(string1.concat(string2));(outputs combined string)
- Example:
-
.indexOf(): Finds the index of the first occurrence of a character or substring.
- Example:
System.out.println(string1.indexOf("llo"));(outputs index where substring "llo" first appears)
- Example:
-
.replace(): Replaces all occurrences of a character or substring with another one (Not shown in example)
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