I want to access the first two digits of a number, and i have tried using substring, substr and slice but none of them work. It's throwing an error saying substring is not defined.
render() {
let trial123 = this.props.buildInfo["abc.version"];
var str = trial123.toString();
var strFirstThree = str.substring(0,3);
console.log(strFirstThree);
}
I have tried the above code
output of(above code)
trial123=19.0.0.1
I need only 19.0
How can i achieve this?
I would split it by dot and then take the first two elements:
const trial = "19.0.0.1"
console.log(trial.split(".").slice(0, 2).join("."))
// 19.0
You could just split and then join:
const [ first, second ] = trial123.split('.');
const result = [ first, second ].join('.');
I have added a code snippet of the work: (explanation comes after it, line by line).
function getFakePropValue(){
return Math.round(Math.random()) == 0 ? "19.0.0.1" : null;
}
let trial123 = getFakePropValue() || "";
//var str = trial123.toString();
// is the toString() really necessary? aren't you passing it along as a String already?
var strFirstThree = trial123.split('.');
//var strFirstThree = str.substring(0,3);
//I wouldn't use substring , what if the address 191.0.0.1 ?
if(strFirstThree.length >= 2)
console.log(strFirstThree.splice(0,2).join("."));
else
console.error("prop was empty");
Because you are using React, the props value was faked with the function getFakePropValue. The code inside is irrelevant, what I am doing is returning a String randomly, in case you have allowed in your React Component for the prop to be empty. This is to show how you an create minimal robust code to avoid having exceptions.
Moving on, the following is a safety net to make sure the variable trial123 always has a string value, even if it's "".
let trial123 = getFakePropValue() || "";
That means that if the function returns something like null , the boolean expression will execute the second apart, and return an empty string "" and that will be the value for trial123.
Moving on, the line where you convert to toString I have removed, I assume you are already getting the value in string format. Next.
var strFirstThree = trial123.split('.');
That creates an array where each position holds a part of the IP addrss. So 19.0.0.1 would become [19,0,0,1] that's thanks to the split by the delimiter . . Next.
if(strFirstThree.length >= 2)
console.log(strFirstThree.splice(0,2).join("."));
else
console.error("prop was empty");
This last piece of code uses the conditional if to make sure that my array has values before I try to splice it and join. The conditional is not to avoid an exception, since splice and join on empty arrays just returns an empty string. It's rather for you to be able to raise an error or something if needed. So if the array has values, I keep the first two positions with splice(0,2) and then join that array with a '.'. I recommend it more than the substr method you were going for because what if you get a number that's 191.0.0.1 then the substr would return the wrong string back, but with splice and join that would never happen.
Things to improve
I would strongly suggest using more human comprehensible variables (reflect their use in the code)
The right path for prop value checking is through Prop.Types, super easy to use, very helpful.
Happy coding!
Related
I've been asked to optimize the speed of my query. I currently have this regex in my query, which is checking for a pattern and returning substring within that pattern. To clarify I have a table with multiple columns that I have to look through to check for this value: [v= and return the numbers within that list.
This is looking through several 'name..' columns that look something like this: xyzzy [v=123] but I only want to return 123, the below works:
COALESCE(REGEXP_SUBSTR(NAME, '[[]v=([0-9]+)', 1, 1, 'ie'),
REGEXP_SUBSTR(NAME_5, '[[]v=([0-9]+)', 1, 1, 'ie'),
REGEXP_SUBSTR(NAME_4, '[[]v=([0-9]+)', 1, 1, 'ie')) as display_vertical_code
but to optimize this, I thought of maybe creating a function unfortunately I don't know javascript :/ and I don't know if the formatting is correct I'm having some difficulties creating it, this is what I've tried, can someone tell me if I'm missing something?
CREATE OR REPLACE FUNCTION dfp.regex(NAME VARCHAR)
RETURNS OBJECT
LANGUAGE javascript
STRICT AS '
return new RegExp(NAME,"[[]v=([0-9]+)",1 ,1,"ie")
';
When I try to use the above function in my below query:
COALESCE(
GET(DFP.REGEX(NAME)),
GET(DFP.REGEX(NAME_5)),
GET(DFP.REGEX(NAME_4)),
GET(DFP.REGEX(NAME_3)),
GET(DFP.REGEX(NAME_2)),
GET(DFP.REGEX(NAME_1)),
GET(DFP.REGEX(NAME_0))
) as display_vertical_code
I see this error:
error line 3 at position 8 not enough arguments for function
[GET(REGEX(Tablename.NAME))], expected 2, got 1
This should do it.
CREATE OR REPLACE FUNCTION regex(NAME VARCHAR)
RETURNS string
LANGUAGE javascript
STRICT IMMUTABLE AS
$$
const regex = /[[]\s{0,5}v\s{0,5}=\s{0,5}([0-9]+)/i;
let s = NAME.match(regex);
if (s != null) {
return s[0].split('=')[1].trim();
} else {
return null;
}
$$;
select regex('xyzzy [v=123]');
-- Alternate permutation
select regex('xyzzy [ v = 123]');
You want to return a string, not an object. Adding the IMMUTABLE option tells Snowflake that the same input results in the same output every time. It can sometimes help with performance.
Edit... This one's a bit more fault tolerant and allows whitespace (if that could be a problem). If you want to get rid of allowing whitespace, delete the \s{0,5} expressions.
I was tasked with a project of creating a CV site were the user uploads a .docx file and the details is extracted from the file and is automatically inputted in the template designed by me,
I have been able to extract the details .docx file with JavaScript and the extracted details was kept in an array to make it easy to identify words with indexing. For example
[Adeola Emmanuel, adeolaemmanuel#gmail.com, pharmacist, 2 ketu ikorodu lagos, etc].
where i need help is not all CV uploaded by the user has the name coming first or email coming second but its sure that they come within 0,6 of the array so i decided to write a function that will help with that but its not working
var email = email(text.slice(0, 5));
function email(email) {
var re = /.{1,}#[^.]{1,}/ig;
if (!re.test(email)) {
email = text.slice(0, 1);
return email;
} else if (re.test(email)) {
email = text.slice(3, 5);
return email;
}
}
You can use the find array method:
function getEmail(arr) {
let re = /\S#[^.\s]/;
return arr.find(str => re.test(str));
}
let text = ["Adeola Emmanuel", "adeolaemmanuel#gmail.com", "pharmacist", "2 ketu ikorodu lagos"];
let email = getEmail(text.slice(0, 5));
console.log(email);
Some remarks:
{1,} in regular expressions can be shortened to just +
You actually don't need to test for multiple occurrences with +, since you would already accept one occurrence. So that also means you would be OK with just one non-point character after the #.
Neither of the regex suffixes (ig) have any use in your regex.
The .test method should get a string as argument, not an array. So you need to pass it email[0] for example.
For a full test of whether some string is a valid email address, the regular expression would be way more complex
When an if condition is false, there is no need to test the exact opposite in the else block: by exclusion that opposite condition will always be true when it gets executed.
The slice of an array is still an array, so returning text.slice(3, 5); in the else block does not make sense. You want to return a string.
You need a loop to inspect other array elements for as long as you don't have a match and have not reached the end of the array. So some loop construct is needed. You can use for, while, or any of the array methods that do such looping. find is particular useful in this case.
Don't give your function the same name as another variable (email) as only one value can be assigned to that variable (a function, a string, or still something else). So in your case you'll lose the function definition by the var initialisation.
I was trying to write a function to check if "str" ends with the given "target". I eventually got the right answer but was wondering what I did wrong with the code I wrote below.
function confirmEnding(str, target) {
var targetArray = target.split("");
var strArray = str.split("");
var ending = [];
for (i=target.length; i>0; i--){
if (strArray[str.length-i]==targetArray[target.length-i]){
ending.push(targetArray[target.length-i]);
} else {
ending.push(0);
}
}
return ending==targetArray;
}
Basically so if the first letters of both str and target are the same, I added it to an array called "ending" and otherwise, added 0. Then once it's done, I would compare the two arrays and it would give me true if str does end with target and false otherwise. It only returned false and I want some insight into this. Could you give me some feedback on this? Thank you.
Since ending and targetArray are two different arrays, even if the contents are same, ending==targetArray; will not give true with '==' operator.
To check the equality of contents of arrays yo will have to iterate over each content and check the equality or if you are particular about '==' you an use
ending.toString() == targetArray.toString()
I can't seem to find an example of anyone using RegEx matches to create an overlay in CodeMirror. The Moustaches example matching one thing at a time seems simple enough, but in the API, it says that the RegEx match returns the array of matches and I can't figure out what to do with it in the context of the structure in the moustaches example.
I have a regular expression which finds all the elements I need to highlight: I've tested it and it works.
Should I be loading up the array outside of the token function and then matching each one? Or is there a way to work with the array?
The other issue is that I want to apply different styling depending on the (biz|cms) option in the regex - one for 'biz' and another for 'cms'. There will be others but I'm trying to keep it simple.
This is as far as I have got. The comments show my confusion.
CodeMirror.defineMode("tbs", function(config, parserConfig) {
var tbsOverlay = {
token: function(stream, state) {
tbsArray = match("^<(biz|cms).([a-zA-Z0-9.]*)(\s)?(\/)?>");
if (tbsArray != null) {
for (i = 0; i < tbsArray.length; i++) {
var result = tbsArray[i];
//Do I need to stream.match each element now to get hold of each bit of text?
//Or is there some way to identify and tag all the matches?
}
}
//Obviously this bit won't work either now - even with regex
while (stream.next() != null && !stream.match("<biz.", false)) {}
return null;
}
};
return CodeMirror.overlayMode(CodeMirror.getMode(config, parserConfig.backdrop || "text/html"), tbsOverlay);
});
It returns the array as produced by RegExp.exec or String.prototype.match (see for example https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/match), so you probably don't want to iterate through it, but rather pick out specific elements the correspond to groups in your regexp (if (result[1] == "biz") ...)
Look at implementation of Code Mirror method match() and you'll see, that it processes method parameter for two types: string and RegExp.
Your constant in
stream.match("<biz.")
is of string type.
Define it in RegExp type:
tbsArray = /<biz./g
Thus, your stream will be matched with RegExp.
Exactly what title asks. I'll provide some examples while explaining my question.
Test string:
var test = "#foo# #foo# bar #foo#";
Say, I want to extract all text between # (all foos but not bar).
var matches = test.match(/#(.*?)#/g);
Using .match as above, it'll store all matches but it'll simply throw away the capturing groups it seems.
var matches2 = /#(.*?)#/g.exec(test);
The .exec method apparently returns only the first result's matched string in the position 0 of the array and my only capturing group of that match in the position 1.
I've exhausted SO, Google and MDN looking for an answer to no avail.
So, my question is, is there any better way to store only the matched capturing groups than looping through it with .exec and calling array.push to store the captured groups?
My expected array for the test above should be:
[0] => (string) foo
[1] => (string) foo
[2] => (string) foo
Pure JS and jQuery answers are accepted, extra cookies if you post JSFiddle with console.log. =]
You can use .exec too like following to build an array
var arr = [],
s = "#foo# #bar# #test#",
re = /#(.*?)#/g,
item;
while (item = re.exec(s))
arr.push(item[1]);
alert(arr.join(' '));
Working Fiddle
Found from Here
Well, it still has a loop, if you dont want a loop then I think you have to go with .replace(). In which case the code will be like
var arr = [];
var str = "#foo# #bar# #test#"
str.replace(/#(.*?)#/g, function(s, match) {
arr.push(match);
});
Check these lines from MDN DOC which explains your query about howexec updates lastIndex property I think,
If your regular expression uses the "g" flag, you can use the exec
method multiple times to find successive matches in the same string.
When you do so, the search starts at the substring of str specified by
the regular expression's lastIndex property (test will also advance
the lastIndex property).
I'm not sure if this is the answer you are looking for but you may try the following code:
var matches = [];
var test = "#foo# #foo# bar #foo#";
test.replace(/#(.*?)#/g, function (string, match) {
matches.push(match);
});
alert(JSON.stringify(matches));
Hope it helps.
data.replace(/.*?#(.*?#)/g, '$1').split(/#/)
No loops, no functions.
In case somebody arrives with a similar need to mine, I needed a matching function for a Django-style URL config handler that could pass path "arguments" to a controller. I came up with this. Naturally it wouldn't work very well if matching '$' but it wouldn't break on '$1.00'. It's a little bit more explicit than necessary. You could just return matchedGroups from the else statement and not bother with the for loop test but ;; in the middle of a loop declaration freaks people out sometimes.
var url = 'http://www.somesite.com/calendar/2014/june/6/';
var calendarMatch = /^http\:\/\/[^\/]*\/calendar\/(\d*)\/(\w*)\/(\d{1,2})\/$/;
function getMatches(str, matcher){
var matchedGroups = [];
for(var i=1,groupFail=false;groupFail===false;i++){
var group = str.replace(matcher,'$'+i);
groupFailTester = new RegExp('^\\$'+i+'$');
if(!groupFailTester.test(group) ){
matchedGroups.push(group);
}
else {
groupFail = true;
}
}
return matchedGroups;
}
console.log( getMatches(url, calendarMatch) );
Another thought, though exec is as efficient.
var s= "#foo# #foo# bar #foo#";
s= s.match(/#([^#])*#/g).join('#').replace(/^#+|#+$/g, '').split(/#+/);