无法使用Javascript访问我的二维数组

Question

this is an array that contains the question on index 0 and choices from 1-4 and then on index 5 contains the answer. I want to access these index numbers individually but cant.

 questionbank = [ ["Which city is the capital of Pakistan", "Islamabad", "Karachi", "Lahore", "Quetta", "Islamabad"], ["Which city is the capital of UAE", "Dubai", "Abu Dhabi", "Sharjah", "Ras Al-Khaimah", "Dubai"], ["Which city is the capital of United States of America", "Austin", "Washington DC", "Boston", "Colorado", "Washington DC"], ["Which city is the capital of UK", "London", "Manchester", "Leeds", "Sunderland", "London"], ["Which city is the capital of Kuwait", "Kuwait City", "Salmiya", "Jahra", "Tokyo", "Kuwait City"], ["Which city is the capital of Saudi Arabia", "Riyadh", "Mecca", "Madinah", "Jeddah", "Riyadh"], ["Which city is the capital of India", "Mumbai", "Delhi", "Bareilly", "Calcutta", "Mumbai"], ["Which city is the capital of Afghanistan", "Kabul", "Kandahar", "Herat", "Jalalabad", "Kabul"], ["Which city is the capital of Ireland", "Dublin", "Belfast", "Cork", "Limerick", "Dublin"] ]; function next_question() { text = questionbank[0, 0]; alert(text); } next_question(); 

The problem is when i call [0,0] the whole sentence in the array comes up instead of just one element in the array. My array is a collection of questions on position 0 and the collection of choices in the other positions. Can you please tell me how to access only one element of the array at a time!

Answer 1

You're not using the correct syntax to access the second dimension. [0, 0] is equivalent to [0] . The comma doesn't separate dimensions, it's the comma operator that simply evaluates both operands and returns the second one. A multi-dimensional array is an array of arrays, so you access each dimension with a separate set of brackets: arrayname[subscript1][subscript2]

 questionbank = [ ["Which city is the capital of Pakistan", "Islamabad", "Karachi", "Lahore", "Quetta", "Islamabad"], ["Which city is the capital of UAE", "Dubai", "Abu Dhabi", "Sharjah", "Ras Al-Khaimah", "Dubai"], ["Which city is the capital of United States of America", "Austin", "Washington DC", "Boston", "Colorado", "Washington DC"], ["Which city is the capital of UK", "London", "Manchester", "Leeds", "Sunderland", "London"], ["Which city is the capital of Kuwait", "Kuwait City", "Salmiya", "Jahra", "Tokyo", "Kuwait City"], ["Which city is the capital of Saudi Arabia", "Riyadh", "Mecca", "Madinah", "Jeddah", "Riyadh"], ["Which city is the capital of India", "Mumbai", "Delhi", "Bareilly", "Calcutta", "Mumbai"], ["Which city is the capital of Afghanistan", "Kabul", "Kandahar", "Herat", "Jalalabad", "Kabul"], ["Which city is the capital of Ireland", "Dublin", "Belfast", "Cork", "Limerick", "Dublin"] ]; function next_question() { text = questionbank[0][0]; alert(text); } next_question(); 

Answer 2

To access to two-dimensional array you should use this notation [0][0] :

 questionbank = [ ["Which city is the capital of Pakistan", "Islamabad", "Karachi", "Lahore", "Quetta", "Islamabad"], ["Which city is the capital of UAE", "Dubai", "Abu Dhabi", "Sharjah", "Ras Al-Khaimah", "Dubai"], ["Which city is the capital of United States of America", "Austin", "Washington DC", "Boston", "Colorado", "Washington DC"], ["Which city is the capital of UK", "London", "Manchester", "Leeds", "Sunderland", "London"], ["Which city is the capital of Kuwait", "Kuwait City", "Salmiya", "Jahra", "Tokyo", "Kuwait City"], ["Which city is the capital of Saudi Arabia", "Riyadh", "Mecca", "Madinah", "Jeddah", "Riyadh"], ["Which city is the capital of India", "Mumbai", "Delhi", "Bareilly", "Calcutta", "Mumbai"], ["Which city is the capital of Afghanistan", "Kabul", "Kandahar", "Herat", "Jalalabad", "Kabul"], ["Which city is the capital of Ireland", "Dublin", "Belfast", "Cork", "Limerick", "Dublin"] ]; function next_question() { text = questionbank[0][0]; alert(text); } next_question(); 

Answer 3

Use the standard notation [dimension][anotherDimension]... in your case [0][0] instead of [0,0] . The last one is not valid in terms of JavaScript or at least does not do what you want. You might have a different background, like C#, where it is a valid multidimensional notation.

Answer 4

这不是questionbank[0, 0]而是questionbank[0][0] 。

Answer 5

这看起来像一个二维数组，因此您应该像这样访问：

questionbank[0][0]