Final answer:
The strpos() function in PHP searches a string for a pattern and returns a positional index if found (true) or false otherwise; option C is correct.
Step-by-step explanation:
The function that searches a string for a pattern, returning true if the pattern exists, and false otherwise, is strpos(). Option C is correct. The strpos() function is used in PHP to find the position of the first occurrence of a substring in a string. If the substring is found, it returns the index of the first occurrence, which is a number greater than or equal to 0, meaning the condition can be treated as true in a boolean context. If the substring is not found, it returns false. The find() and locate() functions do not exist in this context, and grep() is a command-line utility for searching plain-text data sets for lines that match a regular expression.
The correct function to search a string for a pattern and return true if the pattern exists, and false otherwise, is function A) find(). This function is commonly used in programming languages like Python and JavaScript. It can be used to search for a specific pattern or substring within a given string.
For example, in Python, you can use the find() function as follows:
string = 'Hello World' pattern = 'Hello' index = string.find(pattern) if index != -1: print('Pattern found at position:', index) else: print('Pattern not found')
In this example, the find() function searches for the pattern 'Hello' within the given string 'Hello World'. It returns the index of the first occurrence of the pattern, which in this case is 0. If the pattern is not found, the function returns -1.