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I have a list, where I want to group the repeating objects into a single object in the new list. Basically, convert this:
s = ['0.352125', '1', '1', '1', '1', '0', '0', '0', '0', '0', '0', '0', '0', '0.241041', '0.313429', '1', '1']
to this:
s_new = ['0.352125', '4*1','8*0', '0.241041', '0.313429','2*1']
I have tried itertools.groupby() function (python 2.7) as below:
from itertools import groupby
s_g = [list(g) for k, g in groupby(s)]
s_new = [', '.join('{}*{}'.format(sum(1 for _ in g), k) for k, g in groupby(s_g))]
As a result, I get:
s_new = ["1*['0.352125'], 1*['1', '1', '1', '1'], 1*['0', '0', '0', '0', '0', '0', '0', '0'], 1*['0.241041'], 1*['0.313429'], 1*['1', '1']"]
Apparently, this is not the list format I'm trying to get. Could someone please help me with this?
You unnecessarily applied groupby twice and there's also no reason to use str.join.
You can use the following list comprehension instead:
['%s*' % len(l) * (len(l) > 1) + k for k, g in groupby(s) for l in (list(g),)]
import re
fhand = open('sum.txt','r')
number = re.findall('[0-9]'+, fhand)
print number
I am getting syntax error as
number = re.findall('[0-9]'+, fhand)
^
SyntaxError: invalid syntax
Not sure what's going on. Can anybody help?
Read the file contents and declare the entire pattern inside a string literal.
Here is an example:
>>> import re
>>> fhand = open(r'D:\2\_1.txt','r')
>>> fhand
<open file 'D:\\2\\_1.txt', mode 'r' at 0x0282B230>
>>> number = re.findall('[0-9]+', fhand.read())
>>> print number
['1', '2', '3', '1', '0', '2', '0', '7', '0', '2', '2', '0', '3', '0', '5', '0', '3']
>>>
I have a list that i need to write to a .csv Yes, i have done a LOT of looking around (of course i found this link which is close to the target, but misses my case) You see writerows is having all sorts of trouble with the delimiters/formatting in the .csv (the a gets separated from the 1 from the 7 etc etc)
My list looks like this:
buffer = [['a17', 'b17', 'c17', '8', 'e17', 'f17\n'], ['a24', 'b24', 'c24', '6', 'e24', 'f24\n'], ['a27', 'b27', 'c27', '9', 'e27', 'f27\n'], ['a18', 'b18', 'c18', '9', 'e18', 'f18\n'], ['a5', 'b5', 'c5', '5', 'e5', 'f5\n'], ['a20', 'b20', 'c20', '2', 'e20', 'f20\n'], ['a10', 'b10', 'c10', '1', 'e10', 'f10\n'], ['a3', 'b3', 'c3', '3', 'e3', 'f3\n'], ['a11', 'b11', 'c11', '2', 'e11', 'f11\n']]
I can see its like a list of lists so i tried for eachRow in buffer: then following on with a eachRow.split(',') but no good there either.
I just need to write to a .csv it should be easy right... what am i missing?
You can remove the \n string from your buffer like so. Also you have to add newline='' to the with statement in Python 3. See this answer for more detail.
import csv
buffer = [['a17', 'b17', 'c17', '8', 'e17', 'f17\n'],
['a24', 'b24', 'c24', '6', 'e24', 'f24\n'],
['a27', 'b27', 'c27', '9', 'e27', 'f27\n'],
['a18', 'b18', 'c18', '9', 'e18', 'f18\n'],
['a5', 'b5', 'c5', '5', 'e5', 'f5\n'],
['a20', 'b20', 'c20', '2', 'e20', 'f20\n'],
['a10', 'b10', 'c10', '1', 'e10', 'f10\n'],
['a3', 'b3', 'c3', '3', 'e3', 'f3\n'],
['a11', 'b11', 'c11', '2', 'e11', 'f11\n']]
for row_index, list in enumerate(buffer):
for column_index, string in enumerate(list):
buffer[row_index][column_index] = buffer[row_index][column_index].replace('\n', '')
with open('output.csv', 'w', newline='') as f:
writer = csv.writer(f)
writer.writerows(buffer)
import csv
with open('output.csv','w') as f:
writer = csv.writer(f)
writer.writerows(buffer)
Note that the last entry in each of your lists has a newline, so the csvwriter is correctly quoting the string so you end up with "f17\n" (in the first list as an example) which will look strangely formatted if you are not expecting a new line.
I am a newbie at Python 2.7 and used the following code to create the list of observations pulled from a csv file.
import csv
data = []
with open(datafile,'rb') as f:
for row in f:
g=row
data.append(g)
It produces the following list (after reading the first row):
['01/01/2005,01:00,0,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,3,E,9,3,E,9,8.0,A,7,6.0,A,7,87,A,7,1013,A,7,150,A,7,2.1,A,7,16100,A,7,77777,A,7,1.1,E,8,0.099,F,8,0.160,F,8,0,1,A,7']
But when I use the following code to read the csv file and create the list:
data = []
with open(datafile,'rb') as f:
r = csv.reader(f)
for row in f
data = [row for row in r]
I get a list that looks as follows (after reading the first row):
['01/01/2005', '01:00', '0', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '3', 'E', '9', '3', 'E', '9', '8.0', 'A', '7', '6.0', 'A', '7', '87', 'A', '7', '1013', 'A', '7', '150', 'A', '7', '2.1', 'A', '7', '16100', 'A', '7', '77777', 'A', '7', '1.1', 'E', '8', '0.099', 'F', '8', '0.160', 'F', '8', '0', '1', 'A', '7']
This also appears to be a list (with the key difference being the apostrophes around each item in the list instead of just at the beginning and the end).
Since both appear to be lists, why does the code that uses data.append not deliver a similar list?
Your first list has just one single element -- a string holding the entire line, inclusing all the commas.
>>> l1 =['01/01/2005,01:00,0,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,0,2,0,3,E,9,3,E,9,8.0,A,7,6.0,A,7,87,A,7,1013,A,7,150,A,7,2.1,A,7,16100,A,7,77777,A,7,1.1,E,8,0.099,F,8,0.160,F,8,0,1,A,7']
>>> len(l1)
1
In your second example, csv.reader splits this line into several elements and puts those into the list.
>>> l2 = ['01/01/2005', '01:00', '0', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '0', '2', '0', '3', 'E', '9', '3', 'E', '9', '8.0', 'A', '7', '6.0', 'A', '7', '87', 'A', '7', '1013', 'A', '7', '150', 'A', '7', '2.1', 'A', '7', '16100', 'A', '7', '77777', 'A', '7', '1.1', 'E', '8', '0.099', 'F', '8', '0.160', 'F', '8', '0', '1', 'A', '7']
>>> len(l2)
68
Also note that the loop in your second example is somewhat odd. I assume that this is not your actual code, since there's a syntax error in it. It should probably rather be:
r = csv.reader(f)
for row in r: # row in r, not row in f
data.append(row) # append row to data -> 2d-array of items in rows
I am doing one task and I need to find shortest path on graph.
There are no problems at all with algorithm. The problem is how to output paths from source to all other vertexes. Edges has names too, not only weights. How should I initialize matrix of strings correctly? Is it possible at all?
I want this code work:
printf(" -(%s)-> %d", names[prev][next], mas[j]);
mas[j] is array with vertexes
names - array of arrays of string
I am trying to initialize matrix this way:
string names[N][N] = {
{'0', 'A', '0', 'B', 'E', '0', '0', 'P1', '0'},
{'A', '0', 'D', 'I', '0', '0', '0', '0', '0'},
{'0', 'D', '0', '0', '0', 'H', 'F', '0', '0'},
{'B', 'I', '0', '0', '0', 'H', '0', '0', '0'},
{'E', '0', '0', '0', '0', '0', '0', 'P2', '0'},
{'0', '0', 'H', 'H', '0', '0', '0', '0', 'P4'},
{'0', '0', 'F', '0', '0', '0', '0', '0', 'P3'},
{'0', '0', '0', '0', '0', '0', '0', '0', '0'},
{'0', '0', '0', '0', '0', '0', '0', '0', '0'},
};
My programm: http://ideone.com/ZMiVPE
You're using the wrong quotes for string literals. Single quotes ' are used for character literals, and in fact 'P1' is a multi-character literal (which I'm certain you don't even want to mess with). Instead, use double quotes " around your literals.
The reason they all need to be string literals is because there is no std::string constructor that takes only a char. There is, however, a constructor that takes a C-style string (as created by a string literal).
Note that printf will expect a C-style string, so you'll need to do names[prev][next].c_str().