How to replace a line that has a specific text - python
I want to search for particular text and replace the line if the text is present in that line.
In this code I replace line 125, but want to replace dynamically according to the text:
file = open("config.ini", "r")
lines = file.readlines()
lines[125] = "minimum_value_gain = 0.01" + '\n'
f.writelines(lines)
f.close()
How do I make it that if a line has:
minimum_value_gain =
then replace that line with:
minimum_value_gain = 0.01
There is no reason for you to manually parse a config.ini file textually. You should use configparser to make things much simpler. This library reads the file for you, and in a way converts it to a dict so processing the data is much easier. For your task you can do something like:
import configparser
config = configparser.ConfigParser()
config.read("config.ini")
for section in config:
if config.has_option(section, "minimum_value_gain"):
config.set(section, "minimum_value_gain", "0.01")
with open("config.ini", 'w') as f:
config.write(f)
Since you are replacing complete line so if statement will do the trick for you, no need to replace text
#updated make sure one line doesn't have both values
file = open("config.ini", "r")
lines=file.readlines()
newlines = []
for line in lines:
if "minimum_value_gain" in line:
line = "minimum_value_gain = 0.01" + '\n'
if "score_threshold" in line:
line = "Values you want to add"+'\n'
newlines.append(line)
f.writelines(newlines)
f.close()
Little bit messy and not optimized but get's the job the, first readlines and inserts the next_text to the given pos(line). If the line doesn't exists Raises IndexError, else writes to the file
def replace_in_file(filename: str, search_text: str, string_to_add: str) -> None:
with open(filename, "r+") as file_to_write:
lines = file_to_write.readlines()
file_to_write.seek(0)
file_to_write.truncate()
for line in lines:
if line.startswith(search_text):
line = line.rstrip("\n") + string_to_add + "\n"
file_to_write.write(line)
replace_in_file("sdf.txt", "minimum_value_gain", " = 0.01")
You can use also the regex library of Python.
Here is an example.
It is better not to read and write in the same file, that is not good practice. Write in a different file then eventually rename it.
import re
pattern = 'minimum_value_gain'
string_to_replace = 'minimum_value_gain = 0.01\n'
file = open("config.ini", "r")
fileout = open("new_config.ini", "a")
lines=file.readlines()
newlines = [string_to_replace if re.match(pattern, line) else line for line in lines]
f.close()
fileout.writelines(lines)
fileout.close()
You can rename the file afterwards :
import os
os.remove("config.ini")
os.rename("new_config.ini", "config.ini")
Set the string you would like to look for (match_string = 'example')
Have a list output_list that is empty
Use with open(x,y) as z: (this will automatically close the file after completion)
for each line in file.readlines() - run through each line of the file
The if statement adds your replacement line if the match_string is in the line, else just the adds the line
NOTE: All variables can be any name that is not reserved (don't call something just 'list')
match_string = 'example'
output_list = []
with open("config.ini", "r") as file:
for line in file.readlines():
if match_string in line:
output_list.append('minimum_value_gain = 0.01\n')
else:
output_list.append(line)
Maybe not ideal for the first introduction to Python (or more readable) - But I would have done the problem as follows:
with open('config.ini', 'r') as in_file:
out_file = ['minimum_value_gain = 0.01\n' if 'example' in line else line for line in in_file.readlines()]
To replace a specific text in a string
a = 'My name is Zano'
b = a.replace('Zano', 'Zimmer')
Related
How to replace two different lines of text?
I need to create a file that changes the date and name of a .txt, but I can only change one or the other with this code I found on the internet, can anyone give me any tips?
Print
import os
from ast import Str
file = open("example.txt", "r")
replacement = ""
data = "02/07/2022"
name = "Alan"
for line in file:
line = line.strip()
changes = line.replace("__/__/____", data)
replacement = replacement + changes + "\n"
file.close()
fout = open("final.txt", "w")
fout.write(replacement)
fout.close()
You don't need to do this a line a time. You can replace that entire program with this:
data = "02/07/2022"
name = "Alan"
text = open("example.txt", "r").read().replace("__/__/____", data)
open("final.txt", "w").write(text)
Reading from a file reads only the last line in python
I have a problem with python and file reading. When i'm running this code, it reads only the last line from the text file. This is the code:
with open("main.txt", "r") as f:
for line in f:
if line.startswith("console.out(") and line.endswith(")"):
if line.startswith("console.out(\"") and line.endswith("\")"):
consoleFixWS = line.replace("console.out(\"", "")
finalOutWS = consoleFixWS.replace("\")", "")
print(finalOutWS)
The text file:
console.out("Test")
console.out("Test2")
It prints only "Test2" and I tried everything. Thanks in advance.
The first line actually ends with a \n newline character. If you run line = line.strip() before the conditional it will remove any leading and trailing whitespace.
with open("main.txt") as f:
for line in f:
line = line.strip()
if line.startswith("console.out(") and line.endswith(")"):
if line.startswith("console.out(\"") and line.endswith("\")"):
consoleFixWS = line.replace("console.out(\"", "")
finalOutWS = consoleFixWS.replace("\")", "")
print(finalOutWS)
Probably it is your startswith/replace is bugging. Try re module: very nice and flexible:
import re
regex = "console\.out\((?P<text>(.*))\)"
with open("main.txt", "r") as f:
for line in f:
search = re.search(regex, line)
if search:
text = search.group('text')
finalOutWS = text.replace("\\", "")
print(finalOutWS)
Works fine
Eliminate specific number in a data file using Python
I have a large file and I want to delete all the values '24' within the data file. I have used this code but it doesn't do what I want. Suggestions please. Thanks
This is the data file
24,24,24,24,24,24,1000,1000,24,24,24,1000,1000,1000,1000,24,24,24,24,24,24,24,24,24,24,1000,1000,1000,1000,1000,1000,1000,1000,24,24,24,24,1000,1000,1000,1000,24,1000,24,24,24,24,1000,1000,1000,1000,1000,24,24,24,24,24,24,1000,24,24,24,24,1000,1000,1000,1000,1000,1000,1000,1000,1000,24,24,24,24,1000,1000,1000,1000,24,1000,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,1000,1000,24,24,24,24,24,24,1000,1000,1000,24,24,24,24,1000,1000,1000,1000,1000,1000,1000,1000,1000,24,24,24,24,24,24,24,24,24,24,24,24,24,1000,1000,24,24,24,24,24,24,24,24,24,1000,1000,1000,24,24,24,1000,24,24,1000,1000,24,24,24,24,1000,1000,1000,1000,1000,1000,1000,24,24,24,1000,1000,1000,1000,1000,1000,24,24,24,1000,1000,1000,1000,1000,1000,1000,24,24,24,24,1000,1000,24,1000,1000,24,24,1000,1000,1000,1000,1000,1000,1000,24,24,24,1000,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,1000,1000,24,24,24,1000,1000,1000,1000,1000,24,24,24,24,24,24,24,24,1000,1000,1000,1000,1000,24,24,24,24,24,24,1000,24,24,24,24,24,24,24,24,24,1000,1000,1000,1000,1000,1000,24,24,24,24,24,24,24,24,24,24,1000,1000,1000,24,1000,1000,1000,1000,24,24,1000,1000,24,24,24,24,24,24,24,1000,24,24,24,24,24,24,1000,1000,1000,1000,1000,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,24,1000,1000,1000,1000,1000
Code
content = open('txt1.txt', 'r').readlines()
cleandata = []
for line in content:
line = {i:None for i in line.replace("\n", "").split()}
for value in line.copy():
if value == "24":
line.pop(value)
cleandata.append(" ".join(line) + "\n")
open('txt2.txt', 'w').writelines(cleandata)
This should do it:
content = open('txt1.txt', 'r').readlines()
cleandata = []
for line in content:
line = line.replace('24','')
cleandata.append(line)
open('txt2.txt', 'w').writelines(cleandata)
You could use a regex for it, to match the 24 and delete it.
import re
regex24 = re.compile(r"\b24,?\b")
f = open('txt1.txt', 'r')
cleans = [regex24.sub("", line) for line in f.readlines()]
open('txt2.txt', 'w').writelines(cleans)
Python: modify part of a string inside a .cfg file
I want to access a file (C:\Programmer\Test.txt
), find a string inside that file beginning with 'SS' and replace everything after that on the same line with a new string 'C:\Test\Flash'
The code below prints out the line I want to modify but I can't seem to find a suitable function that will replace everything after the 'SS' with the new string.
import re
for line in open('C:\Programmer\Build\Test.txt'):
if line.startswith('SS'):
print(line)
storedline = line
print(storedline)
You can do
file_path = 'C:\Programmer\Build\Test.txt'
new_line_content = 'C:\Test\Flash'
output = []
with open(file_path, 'r') as infile:
line = infile.readline()
while line:
if line[0:2] == 'SS':
output.append('SS{}\n'.format(new_line_content))
else:
output.append(line)
line = infile.readline()
with open(file_path, 'w') as outfile:
outfile.write(''.join(output))
Note that here the detection of the line(s) if line[0:2] == 'SS' is based on interpreting literally your requirement 'find a string inside that file beginning with 'SS''
Reading a textfile into a String
I'm just starting to learn python and have a textfile that looks like this:
Hello
World
Hello
World
And I want to add the numbers '55' to the beggining and end of every string that starts with 'hello'
The numbers '66' to the beggining and every of every string that starts with 'World'
etc
So my final file should look like this:
55Hello55
66World66
55Hello55
66World66
I'm reading the file in all at once, storing it in a string, and then trying to append accordingly
fp = open("test.txt","r")
strHolder = fp.read()
print(strHolder)
if 'Hello' in strHolder:
strHolder = '55' + strHolder + '55'
if 'World' in strHolder:
strHolder = '66' + strHolder + '66'
print(strHolder)
fp.close()
However, my string values '55' and '66' are always being added to the front of the file and end of the file, not the front of a certain string and to the end of the string, where I get this output of the string:
6655Hello
World
Hello
World
5566
Any help would be much appreciated.
You are reading the whole file at once with .read().
You can read it line by line in a for loop.
new_file = []
fp = open("test.txt", "r")
for line in fp:
line = line.rstrip("\n") # The string ends in a newline
# str.rstrip("\n") removes newlines at the end
if "Hello" in line:
line = "55" + line + "55"
if "World" in line:
line = "66" + line + "66"
new_file.append(line)
fp.close()
new_file = "\n".join(new_file)
print(new_file)
You could do it all at once, by reading the whole file and splitting by "\n" (newline)
new_file = []
fp = open("text.txt")
fp_read = fp.read()
fp.close()
for line in fp_read.split("\n"):
if "Hello" # ...
but this would load the whole file into memory at once, while the for loop only loads line by line (So this may not work for larger files).
The behaviour of this is that if the line has "Hello" in it, it will get "55" before and after it (even if the line is " sieohfoiHellosdf ") and the same for "World", and if it has both "Hello" and "World" (e.g. "Hello, World!" or "asdifhoasdfhHellosdjfhsodWorldosadh") it will get "6655" before and after it.
Just as a side note: You should use with to open a file as it makes sure that the file is closed later.
new_file = []
with open("test.txt") as fp: # "r" mode is default
for line in fp:
line = line.rstrip("\n")
if "Hello" in line:
line = "55" + line + "55"
if "World" in line:
line = "66" + line + "66"
new_file.append(line)
new_file = "\n".join(new_file)
print(new_file)
You need to iterate over each line of the file in order to get the desired result. In your code you are using .read(), instead use .readlines() to get list of all lines.
Below is the sample code:
lines = []
with open("test.txt", "r") as f:
for line in f.readlines(): # < Iterate over each line
if line.startswith("Hello"): # <-- check if line starts with "Hello"
line = "55{}55".format(line)
elif line.startswith("World"):
line = "66{}66".format(line)
lines.append(line)
print "\n".join(lines)
Why to use with? Check Python doc:
The ‘with‘ statement clarifies code that previously would use try...finally blocks to ensure that clean-up code is executed. In this section, I’ll discuss the statement as it will commonly be used. In the next section, I’ll examine the implementation details and show how to write objects for use with this statement.
The ‘with‘ statement is a control-flow structure whose basic structure is:
with expression [as variable]: with-block
The expression is evaluated, and it should result in an object that supports the context management protocol (that is, has enter() and exit() methods).
once you have read the file:
read_file = read_file.replace('hello','55hello55')
It'll replace all hellos with 55hello55
and use with open(text.txt, 'r' ) as file_hndler:
To read a text file, I recommend the following way which is compatible with Python 2 & 3:
import io
with io.open("test", mode="r", encoding="utf8") as fd:
...
Here, I make the assumption that your file use uft8 encoding.
Using a with statement make sure the file is closed at the end of reading even if a error occurs (an exception). To learn more about context manager, take a look at the Context Library.
There are several ways to read a text file:
read the whole file with: fd.read(), or
read line by line with a loop: for line in fd.
If you read the whole file, you'll need to split the lines (see str.splitlines. Here are the two solutions:
with io.open("test", mode="r", encoding="utf8") as fd:
content = fd.read()
for line in content.splilines():
if "Hello" in line:
print("55" + line + "55")
if "World" in line:
print("66" + line + "66")
Or
with io.open("test", mode="r", encoding="utf8") as fd:
for line in content.splilines():
line = line[:-1]
if "Hello" in line:
print("55" + line + "55")
if "World" in line:
print("66" + line + "66")
If you need to write the result in another file you can open the output file in write mode and use print(thing, file=out) as follow:
with io.open("test", mode="r", encoding="utf8") as fd:
with io.open("test", mode="w", encoding="utf8") as out:
for line in content.splilines():
line = line[:-1]
if "Hello" in line:
print("55" + line + "55", file=out)
if "World" in line:
print("66" + line + "66", file=out)
If you use Python 2, you'll need the following directive to use the print function:
from __future__ import print_function