I am new to regex so please explain how you got to the answer. Anyway I want to know the best way to match input function from a separate python file.
For example:
match.py
a = input("Enter a number")
b = input()
print(a+b)
Now I want to match ONLY the input statement and replace it with a random number. I will do this in a separate file main.py. So my aim is to replace input function in the match.py with a random numbers so I can check the output will come as expected. You can think of match.py like a coding exercise where he writes the code in that file and main.py will be the file where it evaluates if the users code is right. And to do that I need to replace the input myself and check if it works for all kinds of inputs. I looked for "regex patterns for python input function" but the search did not work right. I have a current way of doing it but I don't think it works in all kinds of cases. I need a perfect pattern which works in all kinds of cases referring to the python syntax. Here is the current main.py I have (It doesn't work for all cases I mean when you write a string with single quote, it does not replace but here is the problem I can just add single quote in pattern but I also need to detect if both are used):
# Evaluating python file checking if input 2 numbers and print sum is correct
import re
import subprocess
input_pattern = re.compile(r"input\s?\([\"]?[\w]*[\"]?\)")
file = open("match.py", 'r')
read = file.read()
file.close()
code = read
matches = input_pattern.findall(code)
for match in matches:
code = code.replace(match, '8')
file = open("match.py", 'w')
file.write(code)
file.close()
process = subprocess.Popen('python3 match.py', stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
out = process.communicate()[0]
print(out == b"16\n")
file = open("match.py", 'w')
file.write(read)
file.close()
Please let me know if you don't understand this question.
The following regex statement is very close to what you need:
input\s?\((?(?=[\"\'])[\"\'].*[\"\']\)|\))
I am using a conditional regex statement. However, I think it may need a nested conditional to avoid the situation that the user enters something like:
input(' text ")
But hopefully this gets you on the right track.
Related
Caveat emptor: I can spell p-y-t-h-o-n and that's pretty much all there is to my knowledge. I tried to take some online classes but after about 20 lectures learning not much, I gave up long time ago. So, what I am going to ask is very simple but I need help:
I have a file with the following structure:
object_name_here:
object_owner:
- me#my.email.com
- user#another.email.com
object_id: some_string_here
identification: some_other_string_here
And this block repeats itself hundreds of times in the same file.
Other than object_name_here being unique and required, all other lines may or may not be present, email addresses can be from none to 10+ different email addresses.
what I want to do is to export this information into a flat file, likes of /etc/passwd, with a twist
for instance, I want the block above to yield a line like this:
object_name_here:object_owner=me#my_email.com,user#another.email.com:objectid=some_string_here:identification=some_other_string_here
again, the number of fields or length of the content fields are not fixed by any means. I am sure this is pretty easy task to accomplish with python but how, I don't know. I don't even know where to start from.
Final Edit: Okay, I am able to write a shell script (bash, ksh etc.) to parse the information, but, when I asked this question originally, I was under the impression that, python had a simpler way of handling uniform or semi-uniform data structures as this one. My understanding was proven to be not very accurate. Sorry for wasting your time.
As jaypb points out, regular expressions are a good idea here. If you're interested in some python 101, I'll give you some simple code to get you started on your own solution.
The following code is a quick and dirty way to lump every six lines of a file into one line of a new file:
# open some files to read and write
oldfile = open("oldfilename","r")
newfile = open("newfilename","w")
# initiate variables and iterate over the input file
count = 0
outputLine = ""
for line in oldfile:
# we're going to append lines in the file to the variable outputLine
# file.readline() will return one line of a file as a string
# str.strip() will remove whitespace at the beginning and end of a string
outputLine = outputLine + oldfile.readline().strip()
# you know your interesting stuff is six lines long, so
# reset the output string and write it to file every six lines
if count%6 == 0:
newfile.write(outputLine + "\n")
outputLine = ""
# increment the counter
count = count + 1
# clean up
oldfile.close()
newfile.close()
This isn't exactly what you want to do but it gets you close. For instance, if you want to get rid of " - " from the beginning of the email addresses and replace it with "=", instead of just appending to outputLine you'd do something like
if some condition:
outputLine = outputLine + '=' + oldfile.readline()[3:]
that last bit is a python slice, [3:] means "give me everything after the third element," and it works for things like strings or lists.
That'll get you started. Use google and the python docs (for instance, googling "python strip" takes you to the built-in types page for python 2.7.10) to understand every line above, then change things around to get what you need.
Since you are replacing text substrings with different text substrings, this is a pretty natural place to use regular expressions.
Python, fortunately, has an excellent regular expressions library called re.
You will probably want to heavily utilize
re.sub(pattern, repl, string)
Look at the documentation here:
https://docs.python.org/3/library/re.html
Update: Here's an example of how to use the regular expression library:
#!/usr/bin/env python
import re
body = None
with open("sample.txt") as f:
body = f.read()
# Replace emails followed by other emails
body = re.sub(" * - ([a-zA-Z.#]*)\n * -", r"\1,", body)
# Replace declarations of object properties
body = re.sub(" +([a-zA-Z_]*): *[\n]*", r"\1=", body)
# Strip newlines
body = re.sub(":?\n", ":", body)
print (body)
Example output:
$ python example.py
object_name_here:object_owner=me#my.email.com, user#another.email.com:object_id=some_string_here:identification=some_other_string_here
I code with python 3.4
and try to solve some task in CodeEval.
The input file consists of lines like:
31415;HYEMYDUMPS
45162;M%muxi%dncpqftiix"
14586214;Uix!&kotvx3
I try to read the inputfile with such way:
import sys
ABC = " !\"#$%&'()*+,-./0123456789:<=>?#ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
test_cases = open(sys.argv[1], 'r')
for test in test_cases:
cod = test.split(';')[0]
phrase = test.split(';')[1]
def decode(cod, phrase):
"""my code"""
def main():
decode(cod, phrase)
if __name__ == '__main__':
main()
Is it the right way to read the inputfile?
Because my solutions' status is "Partially" solved...
What is the right way to read such lines? ( i mean separated with ';' or ' ')
Tnx, Friends!
It is possible that your 'phrase' may contain semi-colons too. When you split you test case line, it might be happening that it breaks your phrase containing semi-colons too into two or more parts. As you are only assigning the first part of these multiple parts to your phrase variable, hence you will get incorrect decoding in such situations.
You, will get 'Partially' solved result as the cases where the phrases do not contain semi-colons will work just fine.
I will like to point out, that this is just my guess. Please provide the text/link of the problem, so that I can take a look and be of better help.
I have a long list of numbers that I would like to input into my code through a raw_input. It includes numbers that are spaced out through SPACES and ENTER/RETURN. The list looks like this . When I try to use the function raw_input, and copy paste the long list of numbers, my variable only retains the first row of numbers. This is my code so far:
def main(*arg):
for i in arg:
print arg
if __name__ == "__main__": main(raw_input("The large array of numbers"))
How can I make my code continue to read the rest of the numbers?
Or if that's not possible, can I make my code acknowledge the ENTER in any way?
P.s. While this is a project euler problem I don't want code that answers the project euler question, or a suggestion to hard code the numbers in. Just suggestions for inputting the numbers into my code.
If I understood your question correctly, I think this code should work (assuming it's in python 2.7):
sentinel = '' # ends when this string is seen
rawinputtext = ''
for line in iter(raw_input, sentinel):
rawinputtext += line + '\n' #or delete \n if you want it all in a single line
print rawinputtext
(code taken from: Raw input across multiple lines in Python )
PS: or even better, you can do the same in just one line!
rawinputtext = '\n'.join(iter(raw_input, '') #replace '\n' for '' if you want the input in one single line
(code taken from: Input a multiline string in python )
I think what you are actually looking for is to directly read from stdin via sys.stdin. But you need to accept the fact that there should be a mechanism to stop accepting any data from stdin, which in this case is feasible by passing an EOF character. An EOF character is passed via the key combination [CNTRL]+d
>>> data=''.join(sys.stdin)
Hello
World
as
a
single stream
>>> print data
Hello
World
as
a
single stream
I would like to be able to search a dictionary in Python using user input wildcards.
I have found this:
import fnmatch
lst = ['this','is','just','a','test', 'thing']
filtered = fnmatch.filter(lst, 'th*')
This matches this and thing. Now if I try to input a whole file and search through
with open('testfilefolder/wssnt10.txt') as f:
file_contents = f.read().lower()
filtered = fnmatch.filter(file_contents, 'th*')
this doesn't match anything. The difference is that in the file that I am reading from I is a text file (Shakespeare play) so I have spaces and it is not a list. I can match things such as a single letter, so if I just have 't' then I get a bunch of t's. So this tells me that I am matching single letters - I however am wanting to match whole words - but even more, to preserve the wildcard structure.
Since what I would like to happen is that a user enters in text (including what will be a wildcard) that I can substitute it in to the place that 'th*' is. The wild card would do what it should still. That leads to the question, can I just stick in a variable holding the search text in for 'th*'? After some investigation I am wondering if I am somehow supposed to translate the 'th*' for example and have found something such as:
regex = fnmatch.translate('th*')
print(regex)
which outputs th.*\Z(?ms)
Is this the right way to go about doing this? I don't know if it is needed.
What would be the best way in going about "passing in regex formulas" as well as perhaps an idea of what I have wrong in the code as it is not operating on the string of incoming text in the second set of code as it does (correctly) in the first.
If the problem is just that you "have spaces and it is not a list," why not make it into a list?
with open('testfilefolder/wssnt10.txt') as f:
file_contents = f.read().lower().split(' ') # split line on spaces to make a list
filtered = fnmatch.filter(file_contents, 'th*')
Write a program that outputs the first number within a file specified by the user. It should behave like:
Enter a file name: l11-1.txt
The first number is 20.
You will need to use the file object method .read(1) to read 1 character at a time, and a string object method to check if it is a number. If there is no number, the expected behaviour is:
Enter a file name: l11-2.txt
There is no number in l11-2.txt.
Why is reading 1 character at a time a better algorithm than calling .read() once and then processing the resulting string using a loop?
I have the files and it does correspond to the answers above but im not sure how to make it output properly.
The code i have so far is below:
filenm = raw_input("Enter a file name: ")
datain=file(filenm,"r")
try:
c=datain.read(1)
result = []
while int(c) >= 0:
result.append(c)
c = datain.read(1)
except:
pass
if len(result) > 0:
print "The first number is",(" ".join(result))+" . "
else:
print "There is no number in" , filenm + "."
so far this opens the file and reads it but the output is always no number even if there is one. Can anyone help me ?
OK, you've been given some instructions:
read a string input from the user
open the file given by that string
.read(1) a character at a time until you get the first number or EOF
print the number
You've got the first and second parts here (although you should use open instead of file to open a file), what next? The first thing to do is to work out your algorithm: what do you want the computer to do?
Your last line starts looping over the lines in the file, which sounds like not what your teacher wants -- they want you to read a single character. File objects have a .read() method that lets you specify how many bytes to read, so:
c = datain.read(1)
will read a single character into a string. You can then call .isdigit() on that to determine if it's a digit or not:
c.isdigit()
It sounds like you're supposed to keep reading a digit until you run out, and then concatenate them all together; if the first thing you read isn't a digit (c.isdigit() is False) you should just error out
Your datain variable is a file object. Use its .read(1) method to read 1 character at a time. Take a look at the string methods and find one that will tell you if a string is a number.
Why is reading 1 character at a time a better algorithm than calling .read() once and then processing the resulting string using a loop?
Define "better".
In this case, it's "better" because it makes you think.
In some cases, it's "better" because it can save reading an entire line when reading the first few bytes is enough.
In some cases, it's "better" because the entire line may not be sitting around in the input buffer.
You could use regex like (searching for an integer or a float):
import re
with open(filename, 'r') as fd:
match = re.match('([-]?\d+(\.\d+|))', fd.read())
if match:
print 'My first number is', match.groups()[0]
This with with anything like: "Hello 111." => will output 111.