Apabila berurusan dengan rentetan CSV (Nilai Dipisahkan Koma) dalam JavaScript, penghuraian boleh menjadi mencabar apabila data boleh mengandungi koma dalam medan yang disebut. Begini cara anda boleh mengendalikan senario ini dengan berkesan dengan penyelesaian terperinci:
Untuk memastikan rentetan input ialah rentetan CSV yang sah , kami mentakrifkan regex pengesahan:
re_valid = r""" # Validate a CSV string having single, double or un-quoted values. ^ # Anchor to start of string. \s* # Allow whitespace before value. (?: # Group for value alternatives. '[^'\]*(?:\[\S\s][^'\]*)*' # Either Single quoted string, | "[^"\]*(?:\[\S\s][^"\]*)*" # or Double quoted string, | [^,'"\s\]*(?:\s+[^,'"\s\]+)* # or Non-comma, non-quote stuff. ) # End group of value alternatives. \s* # Allow whitespace after value. (?: # Zero or more additional values , # Values separated by a comma. \s* # Allow whitespace before value. (?: # Group for value alternatives. '[^'\]*(?:\[\S\s][^'\]*)*' # Either Single quoted string, | "[^"\]*(?:\[\S\s][^"\]*)*" # or Double quoted string, | [^,'"\s\]*(?:\s+[^,'"\s\]+)* # or Non-comma, non-quote stuff. ) # End group of value alternatives. \s* # Allow whitespace after value. )* # Zero or more additional values $ # Anchor to end of string. """
Untuk menghuraikan nilai individu daripada rentetan CSV yang disahkan, kami menggunakan regex berikut:
re_value = r""" # Match one value in valid CSV string. (?!\s*$) # Don't match empty last value. \s* # Strip whitespace before value. (?: # Group for value alternatives. '([^'\]*(?:\[\S\s][^'\]*)*)' # Either : Single quoted string, | "([^"\]*(?:\[\S\s][^"\]*)*)" # or : Double quoted string, | ([^,'"\s\]*(?:\s+[^,'"\s\]+)*) # or : Non-comma, non-quote stuff. ) # End group of value alternatives. \s* # Strip whitespace after value. (?:,|$) # Field ends on comma or EOS. """
Dengan regex ini ditakrifkan, kami boleh melaksanakan fungsi untuk menghuraikan CSV rentetan:
function CSVtoArray(text) { // Return NULL if input string is not well formed CSV string. if (!re_valid.test(text)) return null; var a = []; // Initialize array to receive values. text.replace(re_value, // "Walk" the string using replace with callback. function(m0, m1, m2, m3) { // Remove backslash from \' in single quoted values. if (m1 !== undefined) a.push(m1.replace(/\'/g, "'")); // Remove backslash from \" in double quoted values. else if (m2 !== undefined) a.push(m2.replace(/\"/g, '"')); else if (m3 !== undefined) a.push(m3); return ''; // Return empty string. }); // Handle special case of empty last value. if (/,\s*$/.test(text)) a.push(''); return a; }
Berikut ialah beberapa contoh rentetan CSV input dan output yang dihuraikan yang sepadan:
// Test string from original question let result = CSVtoArray("'string, duppi, du', 23, lala"); console.log(result); // ['string, duppi, du', '23', 'lala'] // Empty CSV string let result = CSVtoArray(""); console.log(result); // [] // CSV string with two empty values let result = CSVtoArray(","); console.log(result); // ['', ''] // Double quoted CSV string having single quoted values let result = CSVtoArray("'one','two with escaped \' single quote', 'three, with, commas'"); console.log(result); // ['one', 'two with escaped \' single quote', 'three, with, commas'] // Single quoted CSV string having double quoted values let result = CSVtoArray('"one","two with escaped \" double quote", "three, with, commas"'); console.log(result); // ['one', 'two with escaped " double quote', 'three, with, commas'] // CSV string with whitespace in and around empty and non-empty values let result = CSVtoArray(" one , 'two' , , ' four' ,, 'six ', ' seven ' , "); console.log(result); // ['one', 'two', '', 'four', '', 'six ', ' seven '] // Not valid let result = CSVtoArray("one, that's me!, escaped \, comma"); console.log(result); // null
Penyelesaian ini memastikan penghuraian tepat rentetan CSV, mengendalikan medan petikan yang mengandungi koma sambil mematuhi keperluan yang ditetapkan.
Atas ialah kandungan terperinci Bagaimanakah JavaScript Boleh Menghuraikan Rentetan CSV dengan Koma dengan Berkesan dalam Medan Dipetik?. Untuk maklumat lanjut, sila ikut artikel berkaitan lain di laman web China PHP!