I have a small script that reads a file. After reading a line i'm trying to figure out that the particular line have a especific text in it. For so i do like this
for line in file:
line = line.lower()
if line.find('my string'):
print ('found my string in the file')
reading the file that line.find aways evaluate to true. When i do like
for line in file:
line = line.lower()
if 'one big line'.find('my string'):
print ('found my string in the file')
It evaluate to false, as it suppose to do. As i'm realy new to python programming just for what i've shown i just cant think of what i might look for...
find returns a number that's the position of the occurring string inside the search string. If it does not find it, it return -1. And every number that's not 0 in python evaluates to True. That's why your code always evaluates to True.
You need something like:
if 'one big line'.find('my string') >= 0:
print ('found my string in the file')
Or, better:
idx = 'one big line'.find('my string')
if idx >= 0:
print ("found 'my string' in position %d" % (idx))
It's better idiomatic python to write this as:
for line in file:
line = line.lower()
if 'my string' in line:
print ('found my string in the file')
rather than using .find() if you don't care about the position within the string.
Related
I have a file named (data.txt):
243521,Biscuit,Flour:Cream,89.5,9,1
367534,Bread,Flour,67.3,1,2
463254,Chocolate,Cocoa butter:Sugar:Milk powder,45.6,4,0
120014,Buns,Wheat Flour,24.9,5,2
560214,Cake,Flour:Baking Powder:Cake Mix,70.5,3,1
123456,burger,bread crumbs:beef:tomato,99.9,10,0
The numbers after the last comma is sold items. I want to write a code that can delete a line just if the number after the last comma is 0. This is the code I wrote but it removes the line even if the number after the last comma is not zero :
productID=input("")
with open("data.txt","r+") as file:
lines= file.readlines()
file.seek(0)
for line in lines:
productInfo= line.split(",")
y=0
if productInfo[5]>"0":
if y==0:
print("Product cannot be removed: sold items must be 0")
y=1
elif productID not in line:
file.write(line)
file.truncate()
print("Product is removed successfully")
I regret that I do not understand what you are asking for. If you have trouble expressing a difficult question, try asking the question to a friend, and then write down what you say.
Other than the noise that y introduces for no reason, the other odd thing about this code is this comparison:
productInfo[5]>"0"
Probably that comparison does not do what you expect.
I believe you just want to know if the last token is a "0" or not. For this it is better to test for equality or inequality, instead of attempting to perform a value comparison of two strings.
String equality can be tested with ==. Check for inequality with !=.
I believe you want this:
productInfo[5] != "0"
From what I have understood, you have a file that contains comma-separated data and last value is of your interest. If that value is 0, you want to remove that line.
General idea is to read the lines in file and split the , in line and access last item. Your mistake is, as many have pointed out, you are trying to compare strings with > which is not valid in python. Following code works for me with your sample data:
#reading the lines in data as list
with open("data.txt", "r") as f:
lines = f.readlines()
new_array = []
#empty array so we can populate it with lines that don't have a 0 at the end
user_input = input("Enter a number: ") #Capturing user input
for line in lines: #iterating over all lines
line = line.split(",") #splitting , in line
if line[len(line)-1].strip() != "0" and line[0] != user_input:
#if first item and last item are not user input and 0 respectively
new_array.append(",".join(line))
elif line[len(line)-1].strip() == "0" and line[0] != user_input:
#if last item is 0 but first item is not user input
new_array.append(",".join(line))
else:
print("ignoring:", *line)
with open("data2.txt", "w") as f: #creating new data file without 0
f.writelines(new_array) #writing new array to new datafile
#data2.txt now contains only lines that have no 0 at the end
I am searching for a string in .gz files and trying to print the last line with a specific string. It is giving me 'list Index is out of range' if the string is not present. Below is the code I was working on
with gzip.open(files, 'r') as r, open ('output.txt', 'w') as w:
string = [line.strip() for line in r.readlines() if b'STRING' in line]
print (string[-1])
With the above code, I can print the last line if the 'STRING' is in the file. If it is not present it is throwing an error. In the else case, I would like to print "NO STRING PRESENT" or something like that. Any help in understanding this will really be helpful. Thanks in advance
Use try-except:
try:
print (string[-1])
except:
print ("NO STRING PRESENT")
or write your own conditional. Start thinking on the lines of the list string itself, what its length would be in either case and then what would you want to do for each case.
I am analysing an episode of Brooklyn 99 specifically trying to find the line number in a text file where Gina says Scully looks 'like an eggplant' but my code isn't working, any help would be appreciated, I am using jupyter and not getting an error message when running my code.
f = open(r'C:\Users\bubba\Downloads\B99_episode_.txt', 'r')
print(f)
# Choosing TERRY
# Initialising the value of count as -1 because it appears in the cast list
count = -1
terry_in_f = f.readlines()
for line in terry_in_f:
if 'TERRY' in line:
count = count + 1
print(count)
# Finding the line number in which Gina states 'like an eggplant'
for index, line in enumerate(f):
if line.lower() == "like an eggplant":
print(index)
break
if "like an eggplant" will always enter the block because "like an eggplant" isn't falsey. You need to check the actual line from the file is equal to the string you're looking for. So it should be if line == "like an eggplant".
Also, you want to print the line number. You can use enumerate() to give you the index of the line you're on instead of just printing the actual line itself.
for index, line in enumerate(f):
if line.lower() == "like an eggplant":
print(index)
break
Lastly, instead of doing a hard comparison of if line == "like an eggplant":, it may be better to do if "like an eggplant" in line:. This will return true if the string "like an eggplant" is in the script line, even if there is some surrounding noise. For example, if the script says "Gina: like an eggplant", having a direct comparison would return false. Checking if the string is inside the line would return True. It gives you more flexibility.
I'm trying to read a csv file, and create a 2 dimensional list from the values stored inside.
However I'm running into trouble when I try to check whether or not the values stored can be converted into floats.
Here is the function I have written, which reads the file and creates a list.
def readfile(amount, name):
tempfile = open(name).readlines()[1:] #First value in line is never a float, hence the [1:]
rain_list = []
count = 0.0
for line in tempfile:
line = line.rstrip()
part = line.split(",")
try:
part = float(part)
except ValueError:
print("ERROR: invalid float in line: {}".format(line))
rain_list.append(part[amount])
count += 1
if count == 0:
print("ERROR in reading the file.")
tempfile.close()
return rain_list
It might be a little messy, since it's essentially a patchwork of different possible solutions I have tried.
The values it gets are the name of the file (name) and the amount of values it reads from the file (amount).
Has anyone got an idea why this does not work as I expect it to work?
part is a list of strings. To check & convert for all floats, you'd have to do:
part = [float(x) for x in part]
(wrapped in your exception block)
BTW you should use the csv module to read comma-separated files. It's built-in. Also using enumerate would allow to be able to print the line where the error occurs, not only the data:
reader = csv.reader(tempfile) # better: pass directly the file handle
# and use next(reader) to discard the title line
for lineno,line in enumerate(reader,2): # lineno starts at 2 because of title line
try:
line = [float(x) for x in line]
except ValueError:
print("ERROR: invalid float in line {}: {}".format(lineno,line))
I am trying to pull a string of input names that get saved to a text file. I need to pull them by capital letter which is input. I.E. the saved text file contains names DanielDanClark, and I need to pull the names that begin with D. I am stuck at this part
for i in range(num):
print("Name",i+1," >> Enter the name:")
n=input("")
names+=n
file=open("names.txt","w")
file.write(names)
lookUp=input("Did you want to look up any names?(Y/N)")
x= ord(lookUp)
if x == 110 or x == 78:
quit()
else:
letter=input("Enter the first letter of the names you want to look up in uppercase:")
file=open("names.txt","r")
fileNames=[]
file.list()
for letter in file:
fileNames.index(letter)
fileNames.close()
I know that the last 4 lines are probably way wrong. It is what I tried in my last failed attempt
Lets break down your code block by block
num = 5
names = ""
for i in range(num)
print("Name",i+1," >> Enter the name:")
n=input("")
names+=n
I took the liberty of giving num a value of 5, and names a value of "", just so the code will run. This block has no problems. And will create a string called names with all the input taken. You might consider putting a delimiter in, which makes it more easier to read back your data. A suggestion would be to use \n which is a line break, so when you get to writing the file, you actually have one name on each line, example:
num = 5
names = ""
for i in range(num)
print("Name",i+1," >> Enter the name:")
n = input()
names += n + "\n"
Now you are going to write the file:
file=open("names.txt","w")
file.write(names)
In this block you forget to close the file, and a better way is to fully specify the pathname of the file, example:
file = open(r"c:\somedir\somesubdir\names.txt","w")
file.write(names)
file.close()
or even better using with:
with open(r"c:\somedir\somesubdir\names.txt","w") as openfile:
openfile.write(names)
The following block you are asking if the user want to lookup a name, and then exit:
lookUp=input("Did you want to look up any names?(Y/N)")
x= ord(lookUp)
if x == 110 or x == 78:
quit()
First thing is that you are using quit() which should not be used in production code, see answers here you really should use sys.exit() which means you need to import the sys module. You then proceed to get the numeric value of the answer being either N or n and you check this in a if statement. You do not have to do ord() you can use a string comparisson directly in your if statement. Example:
lookup = input("Did you want to look up any names?(Y/N)")
if lookup.lower() == "n":
sys.exit()
Then you proceed to lookup the requested data, in the else: block of previous if statement:
else:
letter=input("Enter the first letter of the names you want to look up in uppercase:")
file=open("names.txt","r")
fileNames=[]
file.list()
for letter in file:
fileNames.index(letter)
fileNames.close()
This is not really working properly either, so this is where the delimiter \n is coming in handy. When a text file is opened, you can use a for line in file block to enumerate through the file line by line, and with \n delimiter added in your first block, each line is a name. You also go wrong in the for letter in file block, it does not do what you think it should be doing. It actually returns each letter in the file, regardless of whay you type in the input earlier. Here is a working example:
letter = input("Enter the first letter of the names you want to look up in uppercase:")
result = []
with open(r"c:\somedir\somesubdir\names.txt", "r") as openfile:
for line in openfile: ## loop thru the file line by line
line = line.strip('\n') ## get rid of the delimiter
if line[0].lower() == letter.lower(): ## compare the first (zero) character of the line
result.append(line) ## append to result
print(result) ## do something with the result
Putting it all together:
import sys
num = 5
names = ""
for i in range(num)
print("Name",i+1," >> Enter the name:")
n = input("")
names += n + "\n"
with open(r"c:\somedir\somesubdir\names.txt","w") as openfile:
openfile.write(names)
lookup = input("Did you want to look up any names?(Y/N)")
if lookup.lower() == "n":
sys.exit()
letter = input("Enter the first letter of the names you want to look up in uppercase:")
result = []
with open(r"c:\somedir\somesubdir\names.txt", "r") as openfile:
for line in openfile:
line = line.strip('\n')
if line[0].lower() == letter.lower():
result.append(line)
print(result)
One caveat I like to point out, when you create the file, you open the file in w mode, which will create a new file every time, therefore overwriting the a previous file. If you like to append to a file, you need to open it in a mode, which will append to an existing file, or create a new file when the file does not exist.