substr ( 0, 40 ) // Output: "Tony Stark N" slice ( 0, 40 ) // Output: "Tony Stark N"ĭataRecord. substring ( 0, 40 ) // Output: "Tony Stark N"ĭataRecord. Examples var dataRecord = "Tony Stark N"ĭataRecord. We have the same parameters in all 3 examples, and the name field is the very first ‘field’. We hope that you have got a fair idea as for how we extract a string with all 3 methods.Īs you can see in the below example output, all 3 extraction methods return the same substring in JavaScript. To trace it without any difficulty, I chose ‘N’ as the last character. Then I added the remaining characters with spaces.
In the example that I have used, I just took a sentence and inserted the name “Tony Stark” at the very start. To extract the name field, you may use any of the three standard methods. When you don’t use a character, you will pad it with space. Let’s assume that a row is supposed to have 300 characters whereas a filed named ‘name’ takes the first forty characters. In some cases, fixed width rows are present too in text files.Īs the consumer, you have got a clear idea about the number of characters present in each field. You will come across plenty of field delineators like commas or tabs. When we speak of file formats, we consider them the lowest common denominator. When it comes to a lot of IT systems, flat data files are standard. Work with Fixed Data String using JavaScript Substring, Slice & Substr Methods. In case you pass a negative number as a start, an index will be set to the string length minus value. In case the length or start parameters have NaN, then it will be converted to zero. When we pass a negative number, it will be converted to zero.
When you pass equal values, you will get an empty string as output. Index indexStart has a bigger value compared to inde圎nd, and then the values will be swapped. Same will happen in the case of all the values from NaN to 0. JavaScript substring will be converting all the negative numbers. It’s little different in the case of JavaScript substring. substring ( - 4 ) // "Hello this is test" Negative number examples for string methods var string = "Hello this is test" What if you pass a negative number via slice? In this case, it subtracts the number from the length of the string. What if you pass an invalid value or negative numbers as parameters? rules are in place to deal with such scenarios.
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How to Deal with Negative Numbers using SubString, Substr And Slice Methods in JavaScript?