How do I format the following numbers that are in vector?
For an instance, numbers which I have:
23.02567
0.025679
and I would like to format to this:
0.230256700+E02
0.025679000+E00
First, note that this is not the proper way to format numbers in scientific- or engineering-notation. Those numbers should always have exactly one digit in front of the decimal point, unless the exponent is required to be a multiple of 3 (i.e. a power of 1000, corresponding to one of the SI prefixes). If, however, you have to use this format, you could write your own format string for that.
>>> x, e = 23.02567, 2
>>> "%f%sE%02d" % (x/10**e, "+" if e >= 0 else "-", abs(e))
'0.230257+E02'
>>> x, e = 0.025679, -1
>>> "%f%sE%02d" % (x/10**e, "+" if e >= 0 else "-", abs(e))
'0.256790-E01'
This is assuming that the exponent, e, is given. If the exponent does not matter, you could also use the proper %E format and just replace E+ with +E:
>>> ("%E" % x).replace("E+", "+E").replace("E-", "-E")
'2.567900-E02'
Related
I am totally new to programming.
How do I write a Python script to do the following without using bitwise operators, only allow to use logical and or operators. Thanks in advance!
I'm stuck.
& and
Sets result bit to 1 if both corresponding bits are 1.
E.g. 1010 & 1100 is 1000
| or
Sets result bit to 1 if one of the two corresponding bits is 1.
E.g 1010 | 1100 is 1110
^ xor
Sets result bit to 1 only if one of the corresponding bits is 1.
E.g. 1010 ^ 1100 is 0110
Output:
Enter binary expression: 110110 & 110011
Result: 110010
expr = input('Enter binary expression: ')
n1, op, n2 = expr.split()
n1 = int(n1)
n2 = int(n2)
enter image description here
If you're not allowed to use the bitwise operators, then probably the most straightforward way would be to go bit by bit and do the comparison yourself. This is easiest to do if we represent them as strings
We don't even need to convert the inputs to integers (which can be done by calling int(n1, 2) to specify base-2 instead of base-10), since they're given as strings in binary already. If they were given in base-10, we could read them in as integers and then use the built-in bin() method to represent them as binary strings.
Since there's a method bin() that can represent an integer as a binary string (prefaced with the characters 0b, which we can remove by slicing them off), we can use that, compare digits in the string, then convert the result back into an integer.
expr = input('Enter binary expression: ') # sample: enter "110110 & 110011"
n1, op, n2 = expr.split()
# -------------
result = ''
for (c1, c2) in zip(n1, n2):
next_bit = ""
if op == "&":
next_bit = "1" if (c1 == "1" and c2 == "1") else "0"
elif op == "|":
next_bit = "1" if (c1 == "1" or c2 == "1") else "0"
elif op == "^":
next_bit = "1" if (c1 != c2) else "0"
result += next_bit
print(result)
# 110010
This isn't the most efficient way (you can do some complicated iterative arithmetic and treat the numbers as integers, instead of treating them as strings and just comparing digit by digit), but it's probably the most straightforward and easiest to understand, especially given how the numbers are inputted here.
I am trying to convert a string of varchar to ascii. Then i'm trying to make it so any number that's not 3 digits has a 0 in front of it. then i'm trying to add a 1 to the very beginning of the string and then i'm trying to make it a large number that I can apply math to it.
I've tried a lot of different coding techniques. The closest I've gotten is below:
s = 'Ak'
for c in s:
mgk = (''.join(str(ord(c)) for c in s))
num = [mgk]
var = 1
num.insert(0, var)
mgc = lambda num: int(''.join(str(i) for i in num))
num = mgc(num)
print(num)
With this code I get the output: 165107
It's almost doing exactly what I need to do but it's taking out the 0 from the ord(A) which is 65. I want it to be 165. everything else seems to be working great. I'm using '%03d'% to insert the 0.
How I want it to work is:
Get the ord() value from a string of numbers and letters.
if the ord() value is less than 100 (ex: A = 65, add a 0 to make it a 3 digit number)
take the ord() values and combine them into 1 number. 0 needs to stay in from of 65. then add a one to the list. so basically the output will look like:
1065107
I want to make sure I can take that number and apply math to it.
I have this code too:
s = 'Ak'
for c in s:
s = ord(c)
s = '%03d'%s
mgk = (''.join(str(s)))
s = [mgk]
var = 1
s.insert(0, var)
mgc = lambda s: int(''.join(str(i) for i in s))
s = mgc(s)
print(s)
but then it counts each letter as its own element and it will not combine them and I only want the one in front of the very first number.
When the number is converted to an integer, it
Is this what you want? I am kinda confused:
a = 'Ak'
result = '1' + ''.join(str(f'{ord(char):03d}') for char in a)
print(result) # 1065107
# to make it a number just do:
my_int = int(result)
I have a homework program I have run into a problem with. We basically have to take a word (such as MATLAB) and have the function give us the correct score value for it using the rules of Scrabble. There are other things involved such as double word and double point values, but what I'm struggling with is converting to ASCII. I need to get my string into ASCII form and then sum up those values. We only know the bare basics of strings and our teacher is pretty useless. I've tried converting the string into numbers, but that's not exactly working out. Any suggestions?
function[score] = scrabble(word, letterPoints)
doubleword = '#';
doubleletter = '!';
doublew = [findstr(word, doubleword)]
trouble = [findstr(word, doubleletter)]
word = char(word)
gameplay = word;
ASCII = double(gameplay)
score = lower(sum(ASCII));
Building on Francis's post, what I would recommend you do is create a lookup array. You can certainly convert each character into its ASCII equivalent, but then what I would do is have an array where the input is the ASCII code of the character you want (with a bit of modification), and the output will be the point value of the character. Once you find this, you can sum over the points to get your final point score.
I'm going to leave out double points, double letters, blank tiles and that whole gamut of fun stuff in Scrabble for now in order to get what you want working. By consulting Wikipedia, this is the point distribution for each letter encountered in Scrabble.
1 point: A, E, I, O, N, R, T, L, S, U
2 points: D, G
3 points: B, C, M, P
4 points: F, H, V, W, Y
5 points: K
8 points: J, X
10 points: Q, Z
What we're going to do is convert your word into lower case to ensure consistency. Now, if you take a look at the letter a, this corresponds to ASCII code 97. You can verify that by using the double function we talked about earlier:
>> double('a')
97
As there are 26 letters in the alphabet, this means that going from a to z should go from 97 to 122. Because MATLAB starts indexing arrays at 1, what we can do is subtract each of our characters by 96 so that we'll be able to figure out the numerical position of these characters from 1 to 26.
Let's start by building our lookup table. First, I'm going to define a whole bunch of strings. Each string denotes the letters that are associated with each point in Scrabble:
string1point = 'aeionrtlsu';
string2point = 'dg';
string3point = 'bcmp';
string4point = 'fhvwy';
string5point = 'k';
string8point = 'jx';
string10point = 'qz';
Now, we can use each of the strings, convert to double, subtract by 96 then assign each of the corresponding locations to the points for each letter. Let's create our lookup table like so:
lookup = zeros(1,26);
lookup(double(string1point) - 96) = 1;
lookup(double(string2point) - 96) = 2;
lookup(double(string3point) - 96) = 3;
lookup(double(string4point) - 96) = 4;
lookup(double(string5point) - 96) = 5;
lookup(double(string8point) - 96) = 8;
lookup(double(string10point) - 96) = 10;
I first create an array of length 26 through the zeros function. I then figure out where each letter goes and assign to each letter their point values.
Now, the last thing you need to do is take a string, take the lower case to be sure, then convert each character into its ASCII equivalent, subtract by 96, then sum up the values. If we are given... say... MATLAB:
stringToConvert = 'MATLAB';
stringToConvert = lower(stringToConvert);
ASCII = double(stringToConvert) - 96;
value = sum(lookup(ASCII));
Lo and behold... we get:
value =
10
The last line of the above code is crucial. Basically, ASCII will contain a bunch of indexing locations where each number corresponds to the numerical position of where the letter occurs in the alphabet. We use these positions to look up what point / score each letter gives us, and we sum over all of these values.
Part #2
The next part where double point values and double words come to play can be found in my other StackOverflow post here:
Calculate Scrabble word scores for double letters and double words MATLAB
Convert from string to ASCII:
>> myString = 'hello, world';
>> ASCII = double(myString)
ASCII =
104 101 108 108 111 44 32 119 111 114 108 100
Sum up the values:
>> total = sum(ASCII)
total =
1160
The MATLAB help for char() says (emphasis added):
S = char(X) converts array X of nonnegative integer codes into a character array. Valid codes range from 0 to 65535, where codes 0 through 127 correspond to 7-bit ASCII characters. The characters that MATLAB® can process (other than 7-bit ASCII characters) depend upon your current locale setting. To convert characters into a numeric array, use the double function.
ASCII chart here.
I have a program that takes the columns of a fints-object, multiplies them together pairwise in all combinations and output the result in a new fints object. I have the code for the data, but I also want the series labels to carry through so that the product of column a and b has label a*b.
function tsB = MulTS(tsA)
anames = fieldnames(tsA,1)';
A = fts2mat(tsA);
[i,j] = meshgrid(1:size(A,2),1:size(A,2));
B = Mul(A(:,i(:)),A(:,j(:)));
q = [anames(:,i(:)); anames(:,j(:))];
bnames = strcat(q(1,:),'*', q(2,:));
tsB=fints(tsA.dates, B, bnames);
end
I get warnings when I run it.
tsA= fints([1 2 3]', [[1 1 1]' [2 2 2]'],{'a','b'}');
MulTS(tsA)
??? Error using ==> fints.fints at 188
Illegal name(s) detected. Please check the name(s).
Error in ==> MulTS at 10
tsB=fints(tsA.dates, B, bnames);"
It seems Matlab doesn't like the format of bnames. I've tried googling stuff like "convert cell array to string matlab" and trying things like b = {bnames}. What am I doing wrong?
Your datanames (bnames in MulTS) seems to contain a "*" character, which is illegal according to fints documentation:
datanames
Cell array of data series names. Overrides the default data series names. Default data series names are series1, series2, and so on.
Note: Not all strings are accepted as datanames parameters. Supported data series names cannot start with a number and must contain only these characters:
Lowercase Latin alphabet, a to z
Uppercase Latin alphabet, A to Z
Underscore, _
Try replacing the "*" with "_" or something else.
Many languages have functions for converting string to integer and vice versa. So what happens there? What algorithm is being executed during conversion?
I don't ask in specific language because I think it should be similar in all of them.
To convert a string to an integer, take each character in turn and if it's in the range '0' through '9', convert it to its decimal equivalent. Usually that's simply subtracting the character value of '0'. Now multiply any previous results by 10 and add the new value. Repeat until there are no digits left. If there was a leading '-' minus sign, invert the result.
To convert an integer to a string, start by inverting the number if it is negative. Divide the integer by 10 and save the remainder. Convert the remainder to a character by adding the character value of '0'. Push this to the beginning of the string; now repeat with the value that you obtained from the division. Repeat until the divided value is zero. Put out a leading '-' minus sign if the number started out negative.
Here are concrete implementations in Python, which in my opinion is the language closest to pseudo-code.
def string_to_int(s):
i = 0
sign = 1
if s[0] == '-':
sign = -1
s = s[1:]
for c in s:
if not ('0' <= c <= '9'):
raise ValueError
i = 10 * i + ord(c) - ord('0')
return sign * i
def int_to_string(i):
s = ''
sign = ''
if i < 0:
sign = '-'
i = -i
while True:
remainder = i % 10
i = i / 10
s = chr(ord('0') + remainder) + s
if i == 0:
break
return sign + s
I wouldn't call it an algorithm per se, but depending on the language it will involve the conversion of characters into their integral equivalent. Many languages will either stop on the first character that cannot be represented as an integer (e.g. the letter a), will blindly convert all characters into their ASCII value (e.g. the letter a becomes 97), or will ignore characters that cannot be represented as integers and only convert the ones that can - or return 0 / empty. You have to get more specific on the framework/language to provide more information.
String to integer:
Many (most) languages represent strings, on some level or another, as an array (or list) of characters, which are also short integers. Map the ones corresponding to number characters to their number value. For example, '0' in ascii is represented by 48. So you map 48 to 0, 49 to 1, and so on to 9.
Starting from the left, you multiply your current total by 10, add the next character's value, and move on. (You can make a larger or smaller map, change the number you multiply by at each step, and convert strings of any base you like.)
Integer to string is a longer process involving base conversion to 10. I suppose that since most integers have limited bits (32 or 64, usually), you know that it will come to a certain number of characters at most in a string (20?). So you can set up your own adder and iterate through each place for each bit after calculating its value (2^place).