The other day, while I was putting my kids to sleep, this idea came to me. How do I check if a cell contains a palindrome, using Excel formulas?
Next morning, I wrestled with excel for about 20 minutes and boom, the formula is ready.
Here is how it works:
If you enter a word or phrase in column B, it would tell you whether it is a palindrome or not.
But what is a palindrome?
A palindrome is a word, phrase, verse, or sentence that reads the same backward or forward. For example: A man, a plan, a canal, Panama!
[definition from palindromelist.net]
So, to check if a cell contains palindrome, we need to reverse the cell contents and see if both original and reverse are the same.
For example if B1 contains MAN, then the reverse would be NAM and hence MAN is not a palindrome.
But how do we write a formula to check if a cell has palindrome?
- Assuming B1 contains the word (or phrase), the first step is to clean it. That means, we need to remove any spaces, commas, exclamation marks & other punctuation symbols. So a phrase like “Cigar? Toss it in a can. It is so tragic.” would become “CigarTossitinacanItissotragic”.
- The next step is to match this cleaned text (lets say this will be C1) with the reverse of it.
- But there is no reverse formula. So we use MID() to extract one letter at a time and match it with the corresponding letter from end. (ie first letter with last letter, second letter with second last letter etc.)
- To do this, we use,
MID(C1,ROW(OFFSET($A$1,,,LEN(C1))),1=MID(C1,LEN(C1)-ROW(OFFSET($A$1,,,LEN(C1)))+1,1) - The left portion of this formula would give individual letters in C1 in left to right order and the right portion would give same in reverse order.
- We wrap this in a lovely SUMPRODUCT formula so that we can check for palindrome-ness of B1 using
=IF( SUMPRODUCT( ( MID(C1,ROW(OFFSET($A$1,,,LEN(C1))),1) = MID(C1,LEN(C1)-ROW(OFFSET($A$1,,,LEN(C1)))+1,1)) + 0 ) = LEN(C1), "It’s a Palindrome", "Nah!")
How does this formula work?
Well, that is your weekend homework. Go figure.
One more homework if you are game
If you feel like playing with words, here is another challenge.
How would you test if a cell contains alliteration?
(Alliteration here is defined as sentence where all words begin with same letter)
Go ahead and post your answers using comments.
Download Palindrome Test Excel Workbook
Click here to download the excel workbook and see the palindrome test formulas yourself.
Learn more about Excel Array Formulas
Array formulas are a special class of Excel formulas that can provide powerful results with little work. We have a huge collection of array formula examples on chandoo.org. Go thru below list and see how deep the rabit hole goes.
SUMPRODUCT Formula and how to use it
Advanced SUMPRODUCT Queries
Use Array Formulas to check if a list is sorted
Calculating sum of digits in a number using formulas
Check if a number is Prime using array formulas
More… Excel Array Formulas – Examples & Demos
PS: Monday is our (Indian) Independence Day. So I will see you again on Tuesday.
PPS: On Tuesday, we will be announcing our Excel Formula Crash Course. Get ready.
12 Responses to “29 Excel Formula Tips for all Occasions [and proof that PHD readers truly rock]”
Some great contributions here.
Gotta love the Friday 13th formula 😀
Great tips from you all! Thanks a lot for sharing! bsamson, particularly you helped me on a terribly annoying task. 🙂
(BTW, Chandoo, it's not exactly "Find if a range is normally distributed" what my suggestion does. It checks if two proportions are statistically different. I probably gave you a bad explanation on twitter, but it'd be probably better if you fix it here... 🙂 )
Great compilation Chandoo
For the "Clean your text before you lookup"
=VLOOKUP(CLEAN(TRIM(E20)),F5:G18,2,0)
I would like to share a method to convert a number-stored-as-text before you lookup:
=VLOOKUP(E20+0,F5:G18,2,0)
@Peder, yeah, I loved that formula
@Aires: Sorry, I misunderstood your formula. Corrected the heading now.
@John.. that is a cool tip.
Hey Chandoo,
That p-value formula is really great for a statistics person like me.
What a p-value essentially is, is the probability that the results obtained from a statistical test aren't valid. So for example, if my p value is .05, there's a 5% probability that my results are wrong.
You can play with this if you install the Data Analysis Toolpak (which will perform some statistical tests for you AND provide the P Value.)
Let's say for example I've got two weeks of data (separated into columns) with the number of hours worked per day. I want to find out if the total number of hours I worked in week two were really all the different than week one.
Week1 Week2
10 11
12 9
9 10
7 8
5 8
Go to Data > Data Analysis > T-Test Assuming Unequal Variances > OK
In the Variable 1 Box, select the range of data for week 1.
In the Variable 2 Box, select the range of data for week 2.
Check "Labels"
In the Alpha box, select a value (in percentage terms) for how tolerant you are of error.
.05 is the general standard; that is to say I am willing to accept a 95% level of confidence that my result is accuarate.
Select a range output.
Excel calculates a number of results: Average (mean) for each week's data, etc.
You'll notice however that there are two P Values; one-tail and two-tail. (one tail tests are for > or .05), the number of hours I worked in week two is statistically equivalent to the number of hours I worked in week one.
So here’s a way you might want to use this. You put up a new entry on your blog. You think it’s the best entry ever! So you pull your webstats for this week and compare it to last week. You gather data for each week on the length of time a visitor spends on your website. The question you’re trying to prove statistically is whether there’s an average increase in the amount of time spent on your website this week as compared to last week (as a result of your fancy new blog post). You can run the same statistical test I illustrated above to find out. Incidentally, it matters very little to the stat test whether the quantity of visitors differs or not.
Anyhow, the Data Analysis toolpack doesn't perform a lot of stat tests that folks like me would like to have access to. In those cases I have to either use different software, or write some very complicated mathematical formulas. Having this p-value formula makes my life a LOT easier!
Thanks!
Eric~
Fantastic stuf..One line explanation is cool.
Thanks to all the contributors
OS
Take FirstName, MI, LastName in access (you can fix it to work in excel) capitalize first letter of each and lowercase the rest and add ". " if MI exists then same for last name:
Full Name: Format(Left([FirstName],1),">") & Format(Right([FirstName]),Len([FirstName])-1),"") & ". ","") & Format(Left([LastName],1),">") & Format(Right([LastName],Len([LastName])-1),"<")
I teach excel, access, etc etc for a living and i have my access students build this formula one step at a time from the inside out to show how formulas can be made even if it looks complicated. Yes I know I could just do IsNull([MI]) and reverse the order in the Iif() function but the point here is to nest as many functions as possible one by one (also I illustrate how it will fail without the Not() as it is)
Extract the month from a date
The easiest formula for this is =MONTH(a1)
It will return a 1 for January, 2 for February etc.
if in a column we write the value of total person for eg. 10 if we spent 1.33 paise each person then how we get total amount in next column and the result will in round form plzzzzz solve my problem sir................... thank u
@Anjali
If the value 10 is in B2 and 1.33 paise is in C2 the formula in D2 could be =B2*C2
If the values are a column of values you can copy the formula down by copy/paste or drag the small black handle at the bottom right corner of cell D2
kindly share with me new forumulas.
How to convert a figure like 870.70 into 870 but 871.70 into 880 using excel formula ? Please help.