Filtering and validating El Salvador phone numbers simultaneously is the most efficient approach, as it allows you to process data in one pass and categorize numbers based on their validity and origin. This is particularly useful when dealing with datasets from various sources in a CSV file.
The Core Principle: Define, Normalize, Validate, Classify
The process hinges on these four steps:
Define What an El Salvador Number Is: This involves understanding the country code (+503), the typical 8-digit National Significant Number (NSN) length, and the specific starting digits for landlines (2, 3, 4, 5) and mobile numbers (6, 7). Crucially, remember the special 7-digit and 11-digit numbers for freephone (800) and premium rate (900) services.
Normalize Input Numbers: Phone el-salvador phone number list numbers in real-world data are often inconsistent. They might have spaces, hyphens, parentheses, or even incorrect country codes. Before validation, strip away all non-numeric characters except for a potential leading +. This creates a clean string that can be reliably tested against patterns.
Validate Against El Salvador Patterns: Apply a robust validation method, such as a regular expression or a dedicated library like libphonenumber, to check if the normalized number conforms to any of the defined El Salvador formats.
Classify and Process: Based on the validation result, categorize the number. It's either a valid El Salvador number (and potentially its type: mobile, landline, special) or it's not. You can then direct it to the appropriate output (e.g., a "valid" CSV, an "invalid" CSV, or a log).
Method 1: Simultaneous Filtering and Validation with Regular Expressions
Regular expressions are powerful for this task because a single pattern can encapsulate all valid El Salvador phone number formats. Numbers that don't match this pattern are automatically filtered out.