I have input with floats stored like 1000,50, ie. the decimal points are replaced by commas.
Is there an option in K to load these numbers directly into floats ?
When using
data:("SFF" ;";",";") 0:. filename
I get 0ns, of course, because the numbers are not recognized as floats.
I load them as strings now, and convert them using ssr like
c:.:' .q.ssr'[data;",";"."]
but that is extremely slow.
Is there an option somewhere to have K load these numbers in CCC,CC format as floats directly ? Normal format and ccc,cc format are not mixed, any file has just one of them.
If there is not, I imagine that it must by quite easy to replace a "." somewhere in the Q-binary where the load-function sits, with a ",", to get a version which loads these numbers. Has anybody tried that ? Or any other tip to load big files with these numbers in reasonable time ?
Cheers,
Co
If ssr' is slow for your task you may find this tiny function useful:
c2p:{c:-1_sums count each x;p:ss[r:raze x;","];r[p]:".";(0,c) _ r}
Update: an alternative version:
c2p:{p:ss[r:raze x;","];r[p]:".";(0,-1_sums count'[x])_r}
It concatenates all strings into a single long string, finds positions of commas, replaces commas with periods then splits that long string:
q)N:1000000
q)s:string[N?100000],'",",'string N?1000
q)\t r1:ssr'[s;",";"."]
4284
q)\t r2:c2p s
242
q)r1~r2
1b
I was thinking something like find (?) combined with indexing/applying
q)N:1000000
q)s:string[N?100000],'",",'string N?1000
q)\ts {s[x;y]:"."}./:flip(til count s;s?\:",")
967 52972144
q)s
"93912.794"
"57144.788"
"77809.659"
"7839.47"
"6363.523"
"44761.244"
"65699.712"
It's not perfect but that's the general idea. I'm sure there is an easier way...
Related
I am busy implementing a lab for pen testers to create MD5 hashes from 4 letter words. I need the words to have a combination of lower and uppercase letters as well as numeric and special characters, but I just do not seem to find out how to combine any given characters in all orders. So currently I have this:
my $str = 'aaaa';
print $str++, $/ while $str le 'dddd';
Which will do:
aaaa
aaab
aaac
aaad
...
...
dddd
There is no way however how I can make it do:
Aaaa
AAaa
aAaa
...
dddD
Not even to mention adding numbers and special characters. What I really wanted to do was to make the characters to create words based on a given list. So if I feel I want to use abeDod## it should create all combinations from those characters.
Edit to clarify.
Let's say I give the characters aBc# I need it to give it a a count to say it must have maximum of 4 letters per word and with combination of all the given characters, like:
aBc#
Bac#
caB#
#Bca
...
I hope that clarifies the question.
Use a list of integers that are ASCII codes for the characters you accept, to sample from it using your favorite (pseudo-)random number generator. Then convert each to its character using chr and concatenate them.
Like
perl -wE'$rw .= chr( 32+(int rand 126-32) ) for 1..4; say $rw'
Notes
I use a one-liner merely for easy copy-paste testing. Write this nicely in a script, please
I use the sketchy rand, good for shuffling things a bit. Replace with a better one if needed
Glueing four (pseudo-)random numbers does not build a good distribution; even as each letter on its own does, the whole thing does not. But the four should satisfy most needs.
If not, I think that you'd need to produce a far longer list (range of allowed chars repeated four times perhaps) and randomize it, then draw four-letter subsequences. A lot more work
I need to tap dance a little to produce (random-ish) integers from 32 to 126 using rand, since it takes only the end of range. Also, this takes all of them from that range, likely not what you want; so specify subranges, or specific lists that you want to draw from
I have a matrix where I need to export each column into a separate .csv file.
I know the number of columns and I can achieve my desired result if I specifically select one column to export. I would do this by:
dlmwrite('1.csv',data(:,1), 'precision', 9)
Therefore if I want column 2 I would change the variable to data(:,2) and save this as 2.csv.
So I want a loop that will do all this automatically. I have tried
for i=1:Number_of_Columns
dlmwrite('(i).csv',csv_data(:,(i)), 'precision', 9)
end
which clearly won't work but I am unsure how to do it.
Any help or advice would be much appreciated
Your problem is the filename. If you put i between quotes it will be taken as character instead of a variable. (In your case your filename will always be "(i).csv")
You can concatenate strings using [ ], and since i is an integer you have to convert it to string using num2str()
Try:
for i=1:Number_of_Columns
dlmwrite([num2str(i) '.csv'], csv_data(:,i), 'precision', 9)
end
PD: Since you are storing each column (not each row) in a file, I'm not sure if you want a file where each element is in a separate line, or if you want the column to be stored as a row and separated by commas.
If you want the latter, transpose your column:
dlmwrite([num2str(i) '.csv'], csv_data(:,i).', 'precision', 9)
Note that the transpose operator is .' instead of the complex conjugate ' (this is a common misuse since the results are the same as long as you only use real numbers)
I have a data structure which has data points named Vel1 to Vel1520. However, when I apply Uorder = orderfields(MeanU_Velocity); the variables put in the order Vel1 Vel10 Vel100 Vel1000 Vel1001 Vel1002 etc. Is there any way to sort the data structure such that it lists the variables from 1 to 1520 in ascending order? Regards, Jer
An easy fix to this is to always use the same number of digits. 0001, 0002, ..., 0010, ..., 1520
instead of num2str(42), try sprintf('Vel%04d', 42). This prints formatted text to a string. %04d is a special code that says: fill with zeros, reserve 4 places, print an integer number. Have a look at the documentation and look at matlabs formatted strings tutorial for more comprehensive examples.
I have a txt file that looks like this:
1 17.3
2 18.2
3 18.6
I would like to make a variable (for example temp) which would store store first value (17.3). I would then compare this value with something else (< temp 20). Next step would be to store second value in temp (18.2), so I could again compare values.
Any help would be appreciated!
In Matlab it would look like this:
A=importdata(...)
i=0;
while i<length(temp) do
temp=A(i,2)
i=i+1;
if temp < 20
...
end
end
There are several ways to skin this cat in R6RS:
You can use read. read will read any Scheme datum so since these are all numbers read will read the next number.
You can make your own parser. You read one char at a time and when you hit a space or linefeed you take the list of chars you have though list->string to get string and then string->number This can also be done in two parts reading lines then parsing each line or do a slurp first then process the string.
As the title suggests I'm looking to detect where the numbers are in a string and then to just take the substring from the larger string. EG
If I have say zero89 or eight78, I would just like zero or nine returned. When using the strsplit function I have:
strsplit('zero89', but what do I put here?)
Interested in regexp that will provide you more options to explore with?
Extract numeric digits -
regexp('zero89','\d','match')
Extract anything other than digits -
regexp('zero89','\d+','Split')
strsplit('zero89', '\d', 'DelimiterType', 'RegularExpression')
Or just using regexp:
regexp('zero89','\D+','match')
I got the \D+ from here
Assuming you mean this strsplit?
strsplit('zero89', '8')