I am writing data to a notepad (.txt) file in Python. Entities are separated with commas (','). The file is called 'Database2.txt'.
The variable 'yearlynew' contains a float value that will replace a piece of existing data. I have tried various methods of writing said data to the file but cannot get it to work.
This is the code that I have so far:
g = open('Database2.txt', 'r')
for line in g:
CurrentLine = line.split(',')
if CurrentLine[0] == account:
g = open('Database2.txt', 'a')
#CurrentLine[3] = yearlynew
#g(CurrentLine[3]).write(yearlynew)
#CurrentLine[3].write(yearlynew)
Anything with a '#' before it indicates a failed method that I have tried. If anybody has any suggestions on how to do this I would be very grateful.
I should note that CurrentLine[0] identifies usernames (which are in the first column of the file) so that whichever user is logged in can edit their data and their data only. 'account' holds the username of the user that is currently logged in, and allows the program to trace through the file to find the user's statistics. User data such as names and passwords are stored in a separate file and are not needed for this function.
This is the contents of the file:
Ellie121,0.16,5,60,
Sam232,0.2,6,72,
Heather343,0.1,3,36,
Connor454,0.35,10.5,126,
Ryan565,0.15,4.5,54,
Matthew676,0.22,6.6,79.2,
I don’t think that you can just insert text into a file. I think you will have to write the new data to a different file and then rename it. This is how I would go about it :
import os
account = 'Sam232'
yearlynew = '3.14159'
temp = open ('temporary_file', 'w')
g = open ('Database2.txt', 'r')
for line in g :
CurrentLine = line.split (',')
if CurrentLine [0] == account :
CurrentLine [1] = yearlynew
OutputLine = ','.join (CurrentLine)
temp.write (OutputLine)
g.close ()
temp.close ()
os.remove ('Database2.txt')
os.rename ('temporary_file', 'Database2.txt')
Related
I am trying to save and read the strings which are saved in a text file.
a = [['str1','str2','str3'],['str4','str5','str6'],['str7','str8','str9']]
file = 'D:\\Trails\\test.txt'
# writing list to txt file
thefile = open(file,'w')
for item in a:
thefile.write("%s\n" % item)
thefile.close()
#reading list from txt file
readfile = open(file,'r')
data = readfile.readlines()#
print(a[0][0])
print(data[0][1]) # display data read
the output:
str1
'
both a[0][0] and data[0][0] should have the same value, reading which i saved returns empty. What is the mistake in saving the file?
Update:
the 'a' array is having strings on different lengths. what are changes that I can make in saving the file, so that output will be the same.
Update:
I have made changes by saving the file in csv instead of text using this link, incase of text how to save the data ?
You can save the list directly on file and use the eval function to translate the saved data on file in list again. Isn't recommendable but, the follow code works.
a = [['str1','str2','str3'],['str4','str5','str6'],['str7','str8','str9']]
file = 'test.txt'
# writing list to txt file
thefile = open(file,'w')
thefile.write("%s" % a)
thefile.close()
#reading list from txt file
readfile = open(file,'r')
data = eval(readfile.readline())
print(data)
print(a[0][0])
print(data[0][1]) # display data read
print(a)
print(data)
a and data will not have same value as a is a list of three lists.
Whereas data is a list with three strings.
readfile.readlines() or list(readfile) writes all lines in a list.
So, when you perform data = readfile.readlines() python consider ['str1','str2','str3']\n as a single string and not as a list.
So,to get your desired output you can use following print statement.
print(data[0][2:6])
I need to search for a name in a file and in the line starting with that name, I need to replace the fourth item in the list that is separated my commas. I have began trying to program this with the following code, but I have not got it to work.
with open("SampleFile.txt", "r") as f:
newline=[]
for word in f.line():
newline.append(word.replace(str(String1), str(String2)))
with open("SampleFile.txt", "w") as f:
for line in newline :
f.writelines(line)
#this piece of code replaced every occurence of String1 with String 2
f = open("SampleFile.txt", "r")
for line in f:
if line.startswith(Name):
if line.contains(String1):
newline = line.replace(str(String1), str(String2))
#this came up with a syntax error
You could give some dummy data which would help people to answer your question. I suppose you to backup your data: You can save the edited data to a new file or you can backup the old file to a backup folder before working on the data (think about using "from shutil import copyfile" and then "copyfile(src, dst)"). Otherwise by making a mistake you could easily ruin your data without being able to easily restore them.
You can't replace the string with "newline = line.replace(str(String1), str(String2))"! Think about "strong" as your search term and a line like "Armstrong,Paul,strong,44" - if you replace "strong" with "weak" you would get "Armweak,Paul,weak,44".
I hope the following code helps you:
filename = "SampleFile.txt"
filename_new = filename.replace(".", "_new.")
search_term = "Smith"
with open(filename) as src, open(filename_new, 'w') as dst:
for line in src:
if line.startswith(search_term):
items = line.split(",")
items[4-1] = items[4-1].replace("old", "new")
line = ",".join(items)
dst.write(line)
If you work with a csv-file you should have a look at the csv module.
PS My files contain the following data (the filenames are not in the files!!!):
SampleFile.txt SampleFile_new.txt
Adams,George,m,old,34 Adams,George,m,old,34
Adams,Tracy,f,old,32 Adams,Tracy,f,old,32
Smith,John,m,old,53 Smith,John,m,new,53
Man,Emily,w,old,44 Man,Emily,w,old,44
I am using a microstacknode accelerometer and intend to save it into csv file.
while True:
numpy.loadtxt('foo.csv', delimiter=",")
raw = accelerometer.get_xyz(raw=True)
g = accelerometer.get_xyz()
ms = accelerometer.get_xyz_ms2()
a = numpy.asarray([[raw['x'],raw['y'],raw['z']]])
numpy.savetxt("foo.csv",a,delimiter=",",newline="\n")
However, the saving is only done on 1 line. Any help given? Still quite a noobie on python.
NumPy is not the best solution for this type of things.
This should do what you intend:
while True:
raw = accelerometer.get_xyz(raw=True)
fobj = open('foo.csv', 'a')
fobj.write('{},{},{}\n'.format(raw['x'], raw['y'], raw['z']))
fobj.close()
Here fobj = open('foo.csv', 'a') opens the file in append mode. So if the file already exists, the next writing will go to the end of file, keeping the data in the file.
Let's have look at your code. This line:
numpy.loadtxt('foo.csv', delimiter=",")
reads the whole file but doe not do anything with the at it read, because you don't assign to a variable. You would need to do something like this:
data = numpy.loadtxt('foo.csv', delimiter=",")
This line:
numpy.savetxt("foo.csv",a,delimiter=",",newline="\n")
Creates a new file with the name foo.csv overwriting the existing one. Therefore, you see only one line, the last one written.
This should do the same but dos not open and close the file all the time:
with open('foo.csv', 'a') as fobj:
while True:
raw = accelerometer.get_xyz(raw=True)
fobj.write('{},{},{}\n'.format(raw['x'], raw['y'], raw['z']))
The with open() opens the file with the promise to close it even in case of an exception. For example, if you break out of the while True loop with Ctrl-C.
I have 4 lists called I_list, Itiso, ItHDKR and Itperez and I would like to receive .txt output files with the data of these lists. I am trying to make Python rename automatically the name of the .txt output files in terms of some of my input data. In this way, the .txt output files will always have different names.
Now I am programming the following commands:
Horizontal_radiation = []
Isotropic_radiation = []
HDKR_radiation = []
Perez_radiation = []
Horizontal = open("outputHorizontal.txt", 'w')
Isotropic = open("outputIsotropic.txt", 'w')
HDKR = open("outputHDKR.txt", 'w')
Perez = open("outputPerez.txt", 'w')
for i in I_list:
Horizontal_radiation.append(i)
for x in Itiso:
Isotropic_radiation.append(x)
for y in ItHDKR:
HDKR_radiation.append(y)
for z in Itperez:
Perez_radiation.append(z)
Horizontal.write(str(Horizontal_radiation))
Isotropic.write(str(Isotropic_radiation))
HDKR.write(str(HDKR_radiation))
Perez.write(str(Perez_radiation))
Horizontal.close()
Isotropic.close()
HDKR.close()
Perez.close()
As you can see, the name of the .txt output file is fixed as "outputHorizontal.txt" (the first one). Is there any way to change this name and put it according to a input? For example, one of my inputs is the latitude, as 'lat'. I am trying to make the output file name be expressed in terms of 'lat', in this way everytime I run the program the name would be different, because now I always get the same name and the file is overwritten.
Thank you very much people, kind regards.
You can pass a string variable as the output file name. For example you could move the file declarations after you add elements to the lists (and before you write them) and use
Horizontal = open(str(Horizontal_radiation[0]), 'w')
Or just add a timestamp to the file name if it's all about don't overwriting files
Horizontal = open("horizontal-%s".format(datetime.today()), 'w')
I am using MATLAB to process data from files. I am writing a program that takes input from the user and then locates the particular files in the directory graphing them. Files are named:
{name}U{rate}
{name} is a string representing the name of the computer. {rate} is a number. Here is my code:
%# get user to input name and rate
NET_NAME = input('Enter the NET_NAME of the files: ', 's');
rate = input('Enter the rate of the files: ');
U = strcat(NET_NAME, 'U', rate)
load U;
Ux = U(:,1);
Uy = U(:,2);
There are currently two problems:
When I do the strcat with say 'hello', 'U', and rate is 50, U will store 'helloU2' - how can I get strcat to append {rate} properly?
The load line - how do I dereference U so load tries to load the string stored in U?
Many thanks!
Mikhail's comment above solves your immediate problem.
A more user-friendly way of selecting a file:
[fileName,filePath] = uigetfile('*', 'Select data file', '.');
if filePath==0, error('None selected!'); end
U = load( fullfile(filePath,fileName) );
In addition to using SPRINTF like Mikhail suggested, you can also combine strings and numeric values by first converting the numeric values to strings using functions like NUM2STR and INT2STR:
U = [NET_NAME 'U' int2str(rate)];
data = load(U); %# Loads a .mat file with the name in U
One issue with the string in U is that the file has to be on the MATLAB path or in the current directory. Otherwise, the variable NET_NAME has to contain a full or partial path like this:
NET_NAME = 'C:\My Documents\MATLAB\name'; %# A complete path
NET_NAME = 'data\name'; %# data is a folder in the current directory
Amro's suggestion of using UIGETFILE is ideal because it helps you to ensure you have a complete and correct path to the file.