Can anyone please direct me to an example of where one can send a user input variable to a checking function or module & return the validated input assigning / updating the initialised variable?. I am trying to re-create something I did in C++ many years ago where I am trying to validate an integer! In this particular case that the number of bolts input in a building frame connection is such. Any direction would be greatly appreciated as my internet searches and trawls through my copy of Python A Crash Course have yet to shed any light! Many thanks in anticipation that someone will feel benevolent towards a Python newbie!
Regards Steve
Below is one on my numerous attempts at this, really I would just like to abandon and use While and a function call. In this one apparently I am not allowed to put > (line 4) between str and int, this desite my attempt to force N to be int - penultimate line!
def int_val(N):
#checks
# check 1. n > 0 for real entries
N > 0
isinstance(N, int)
N=N
return N
print("N not ok enter again")
#N = input("Input N the Number of bolts ")
# Initialiase N=0
#N = 0
# Enter the number of bolts
N = input("Input N the Number of bolts ")
int_val(N)
print("no of bolts is", N)
Is something like this what you have in mind? It takes advantage of the fact that using the built-in int function will convert a string to an integer if possible, but otherwise throw a ValueError.
def str_to_posint(s):
"""Return value if converted and greater than zero else None."""
try:
num = int(s)
return num if num > 0 else None
except ValueError:
return None
while True:
s = input("Enter number of bolts: ")
if num_bolts := str_to_posint(s):
break
print(f"Sorry, \"{s}\" is not a valid number of bolts.")
print(f"{num_bolts = }")
Output:
Enter number of bolts: twenty
Sorry, "twenty" is not a valid number of bolts.
Enter number of bolts: 20
num_bolts = 20
def str_to_posint(s):
"""Return value if converted and greater than zero else None."""
try:
num = int(s)
return num if num > 0 else None
except ValueError:
return None
while True:
s = input("Enter number of bolts: ")
if num_bolts := str_to_posint(s):
break
print(f"Sorry, "{s}" is not a valid number of bolts.")
print(f"{num_bolts = }")
Related
I've got a little MatLab script, which I try to understand. It doesn't do very much. It only reads a text from a file and encode and decode it with the Huffman-functions.
But it throws an error while decoding:
"error: out of memory or dimension too large for Octave's index type
error: called from huffmandeco>dict2tree at line 95 column 19"
I don't know why, because I debugged it and don't see a large index type.
I added the part which calculates p from the input text.
%text is a random input text file in ASCII
%calculate the relative frequency of every Symbol
for i=0:127
nlet=length(find(text==i));
p(i+1)=nlet/length(text);
end
symb = 0:127;
dict = huffmandict(symb,p); % Create dictionary
compdata = huffmanenco(fdata,dict); % Encode the data
dsig = huffmandeco(compdata,dict); % Decode the Huffman code
I can oly use octave instead of MatLab. I don't know, if there is an unexpected error. I use the Octave Version 6.2.0 on Win10. I tried the version for large data, it didn't change anything.
Maybe anyone knows the error in this context?
EDIT:
I debugged the code again. In the function huffmandeco I found the following function:
function tree = dict2tree (dict)
L = length (dict);
lengths = zeros (1, L);
## the depth of the tree is limited by the maximum word length.
for i = 1:L
lengths(i) = length (dict{i});
endfor
m = max (lengths);
tree = zeros (1, 2^(m+1)-1)-1;
for i = 1:L
pointer = 1;
word = dict{i};
for bit = word
pointer = 2 * pointer + bit;
endfor
tree(pointer) = i;
endfor
endfunction
The maximum length m in this case is 82. So the function calculates:
tree = zeros (1, 2^(82+1)-1)-1.
So it's obvious why the error called a too large index type.
But there must be a solution or another error, because the code is tested before.
I haven't weeded through the code enough to know why yet, but huffmandict is not ignoring zero-probability symbols the way it claims to. Nor have I been able to find a bug report on Savannah, but again I haven't searched thoroughly.
A workaround is to limit the symbol list and their probabilities to only the symbols that actually occur. Using containers.Map would be ideal, but in Octave you can do that with a couple of the outputs from unique:
% Create a symbol table of the unique characters in the input string
% and the indices into the table for each character in the string.
[symbols, ~, inds] = unique(textstr);
inds = inds.'; % just make it easier to read
For the string
textstr = 'Random String Input.';
the result is:
>> symbols
symbols = .IRSadgimnoprtu
>> inds
inds =
Columns 1 through 19:
4 6 11 7 12 10 1 5 15 14 9 11 8 1 3 11 13 16 15
Column 20:
2
So the first symbol in the input string is symbols(4), the second is symbols(6), and so on.
From there, you just use symbols and inds to create the dictionary and encode/decode the signal. Here's a quick demo script:
textstr = 'Random String Input.';
fprintf("Starting string: %s\n", textstr);
% Create a symbol table of the unique characters in the input string
% and the indices into the table for each character in the string.
[symbols, ~, inds] = unique(textstr);
inds = inds.'; % just make it easier to read
% Calculate the frequency of each symbol in table
% max(inds) == numel(symbols)
p = histc(inds, 1:max(inds))/numel(inds);
dict = huffmandict(symbols, p);
compdata = huffmanenco(inds, dict);
dsig = huffmandeco(compdata, dict);
fprintf("Decoded string: %s\n", symbols(dsig));
And the output:
Starting string: Random String Input.
Decoded string: Random String Input.
To encode strings other than the original input string, you would have to map the characters to symbol indices (ensuring that all symbols in the string are actually present in the symbol table, obviously):
>> [~, s_idx] = ismember('trogdor', symbols)
s_idx =
15 14 12 8 7 12 14
>> compdata = huffmanenco(s_idx, dict);
>> dsig = huffmandeco(compdata, dict);
>> fprintf("Decoded string: %s\n", symbols(dsig));
Decoded string: trogdor
Please help as soon as possible...
Write a MIPS assembly language program that prompts the user to input two strings (each should be no longer than 50 characters including the null terminator). Your program should determine whether the second string is a substring of the first. If it is, then your program should print out the first index in which the second string appears in the first. For example, if the first string is “Hello World” and the second string is “lo”, then the program should print out 3, i.e. the starting index of “lo” in “Hello World.” If the second string is not contained in the first string, then your program should print out -1.
To be able to understand what you have to implement at assembly level, the first thing you should do, is understanding the high-level algorithm. Why?
It's easier for you to see all the cases and edge-cases in time!
To look back at what have I been trying to do again? in the middle of programming the Assembly version.
To quickly see which variables you (certainly) need.
I wrote following program (forgive me, python has been a while for me):
def is_in_string_1(string, substring):
"""
aaba: a, b, ab, ba, aba (last one will fail)
"""
length = len(string)
sublength = len(substring)
if (sublength == 0):
return True
j = 0
for i in range(0, length):
if string[i] != substring[j]:
j = 0
else:
j += 1
if j == sublength:
return True
return False
def is_in_string_2(string, substring):
"""
aaba: a, b, ab, ba, aba
"""
length = len(string)
sublength = len(substring)
for i in range(0, length + 1 - sublength): # string: aabc; substring: c; length: 4; sublength: 1; indexes: 0,1,2,3;
is_substring = True
for j in range(0, sublength): # for the sake of the algorithm, no slicing here
if string[i+j] != substring[j]:
is_substring = False
break
if is_substring:
return True
return False
stringTuples = [
("aaa", "aa"),
("aaa", "aaa"),
("aaa", "aab"),
("abc", "bc"),
("abc", "a"),
("abc", "abc"),
("aaa", ""),
("aaa", "b")
]
for stringTuple in stringTuples:
print(
stringTuple[0],
stringTuple[1],
':',
is_in_string_1(stringTuple[0], stringTuple[1]),
is_in_string_2(stringTuple[0], stringTuple[1]),
sep='\t'
)
I first thought I could optimize the standard solution (is_in_string_2), leaving out the second for-loop (is_in_string_1), but after some thinking I already found out it would fail (the edge-case wasn't even in any of my test-data!) - so I left it as an example for how important it is that you use a correct algorithm.
The program produces the following output:
aaa aa : True True
aaa aaa : True True
aaa aab : False False
abc bc : True True
abc a : True True
abc abc : True True
aaa : True True
aaa b : False False
aaba aba : False True
Notice how all output was correct, except for the last line, where the first algorithm is wrong.
Before you continue:
You have to make your own len() function in MIPS; note that all string are (if I remember correctly) null terminated, so you'll have to count all non-null characters of a string, or in other words, count how many characters precede the null-terminator.
You should use j, $ra and jr calls to go to a "function" or subroutines. (Search)
While in one, you can call other functions using the stack. (Search)
I'm new to Python and I believe the issue with my code is being caused by the fact that I'm a newbie and there's some theory or something that I must not be familiar with yet.
Yes, this question was asked before but, is different from mine. Believe me I tried everything that I thought that needs to be done.
Everything worked until I added everything in "if five in silos" statement.
After I enter the values for the 6 input functions, the program just finishes with exit code 0. Nothing else happens. The for loop is not initiated.
I want for the code to accept either 103 or 106 when prompting to enter something for the "five" variable.
I'm using PyCharm and Python 3.7.
import mysql.connector
try:
db = mysql.connector.connect(
host="",
user="",
passwd="",
database=""
)
one = int(input("Number of requested telephone numbers: "))
two = input("Enter the prefix (4 characters) with a leading 0: ")[:4]
three = int(input("Enter the ccid: "))
four = int(input("Enter the cid: "))
six = input("Enter case number: ")
five = int(input("Enter silo (103, 106 only): "))
cursor = db.cursor()
cursor.execute(f"SELECT * FROM n1 WHERE ddi LIKE '{two}%' AND silo = 1 AND ccid = 0 LIMIT {one}")
cursor.fetchall()
silos = (103, 106)
if five in silos:
if cursor.rowcount > 0:
for row in cursor:
seven = input(f"{row[1]} has been found on our system. Do you want to continue? Type either Y or N.")
if seven == "Y":
cursor.execute(f"INSERT INTO n{five} (ddi, silo, ccid, campaign, assigned, allocated, "
f"internal_notes, client_notes, agentid, carrier, alias) VALUES "
f"('{row[1]}', 1, {three}, {four}, NOW(), NOW(), 'This is a test.', '', 0, "
f"'{row[13]}', '') "
f"ON DUPLICATE KEY UPDATE "
f"silo = VALUES (silo), "
f"ccid = VALUES (ccid), "
f"campaign = VALUES (campaign);")
cursor.execute(f"UPDATE n1 SET silo = {five}, internal_notes = '{six}', allocated = NOW() WHERE "
f"ddi = '{row[1]}'")
else:
print("The operation has been canceled.")
db.commit()
else:
print(f"No results for prefix {two}.")
else:
print("Enter either silo 103 or 106.")
cursor.close()
db.close()
except (ValueError, NameError):
print("Please, enter an integer for all questions, except case number.")
Because it must be:
for row in cursor.fetchall():
// do something
In your code cursor returns a Python Class defined by db.cursor() but you need to call the fetchall() function to read the rows contained in it.
You're actually calling cursor.fetchall() without doing nothing with it, you can assign the call to a variable and than do this:
result = cursor.fetchall()
for row in result:
//do something
I found the problem: I had to store cursor.fetchall() into a variable.
After I put: eight = cursor.fetchall() before the "silos" tuple, everything worked perfectly.
Hello guys would like help with the following question:
You are to design an algorithm to describe the following:
A function is required that converts a text representation of a binary number to an integer. The binary number may be any length from one (1) to eight (8) digits.
Be sure to check that the text string contains only 0s and 1s.
For example:
Input Output
101 5
1101001 105
10011R Not a valid binary number
Here is what I have come up with so far in pseudo code... P.S complete beginner
READ inputValue
SET intValue = inputValue TO INTEGER
SET n = 0
WHILE n < 8 DO
IF intValue = 1
SET n = n + 1
PRINT intValue
ELSE IF intValue = 0
PRINT intValue
REPEAT
ELSE
PRINT Sorry we are not able to validate your input
ENDIF
ENDIF
outValue = n.CALCULATE BINARY OUTPUT
PRINT outValue
Would like if someone can provide some tips on answering this
The way you compute the value your binary number is incorrect. 101 represents 1*2^2+0*2^1+1*2^0=5.
Here is how you could read and convert one sample.
set n=0
set flag=valid
while read char into c and c not= end_of_line
if c = '1'
set n = 2*n+1
else if c='0'
set n=2*n
else
set flag=invalid
endif
endwhile
if flag=invalid
print Sorry we are not able to validate your input
else
print n
endif
I am trying to make a program that has a user input numbers into multiple different lines of code and I am trying to make it so that if the user inputs something other than a number the program will ask the user again to input the number correctly. I was trying to define a function that I could use for all of them but every time I run the program, it crashes. Any help would be much appreciated, thank you.
My code:
def error():
global m1
global m2
global w1
global w2
while True:
try:
int(m1 or m2 or w1 or w2)
except ValueError:
try:
float(m1 or m2 or w1 or w2)
except ValueError:
m1 or m2 or w1 or w2=input("please input your response correctly...")
break
m1=input("\nWhat was your first marking period percentage?")
error()
w1=input("\nWhat is the weighting of the first marking period? (in decimal)")
error()
m2=input("\nWhat was your second marking period percentage?")
error()
w2=input("\nWhat is the weighting of the second marking period? (in decimal)")
error()
def user_input(msg):
inp = input(msg)
try:
return int(inp) if inp.isnumeric() else float(inp)
except ValueError as e:
return user_input("Please enter a numeric value")
m1=user_input("\nWhat was your first marking period percentage?")
w1=user_input("\nWhat is the weighting of the first marking period? (in decimal)")
m2=user_input("\nWhat was your second marking period percentage?")
w2=user_input("\nWhat is the weighting of the second marking period? (in decimal)")
You should write your function to get one number at a time. If at exception is triggered somewhere, it should be handled. Note how the get_number function shown below will keep asking for a number but also shows the prompt specified by its caller. If you are not running Python 3.6 or higher, you will need to comment out the call to print in the main function.
#! /usr/bin/env python3
def main():
p1 = get_number('What is your 1st marking period percentage? ')
w1 = get_number('What is the weighting of the 1st marking period? ')
p2 = get_number('What is your 2nd marking period percentage? ')
w2 = get_number('What is the weighting of the 2nd marking period? ')
score = calculate_score((p1, p2), (w1, w2))
print(f'Your score is {score:.2f}%.')
def get_number(prompt):
while True:
try:
text = input(prompt)
except EOFError:
raise SystemExit()
else:
try:
number = float(text)
except ValueError:
print('Please enter a number.')
else:
break
return number
def calculate_score(percentages, weights):
if len(percentages) != len(weights):
raise ValueError('percentages and weights must have same length')
return sum(p * w for p, w in zip(percentages, weights)) / sum(weights)
if __name__ == '__main__':
main()
By the following code you can able to make a function that only accept integer value:
def input_type(a):
if(type(10)==type(a)):
print("integer")
else:
print("not integer")
a=int(input())
input_type(a)