Change specific value in CSV file via Python
I need the way to change specific value of the column of csv file. For example I have csv file:
"Ip","Sites"
"127.0.0.1",10
"127.0.0.2",23
"127.0.0.3",50
and I need to change value 23 to 30 of the "127.0.0.2".
I use csv library: import csv
Appreciate any help as I'm new in Python. Thanks!
python csv filereader
asked Jun 14 '12 at 13:00
ihorko
3,570206198
add a comment |
I need the way to change specific value of the column of csv file. For example I have csv file:
"Ip","Sites"
"127.0.0.1",10
"127.0.0.2",23
"127.0.0.3",50
and I need to change value 23 to 30 of the "127.0.0.2".
I use csv library: import csv
Appreciate any help as I'm new in Python. Thanks!
python csv filereader
asked Jun 14 '12 at 13:00
ihorko
3,570206198
So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13
add a comment |
I need the way to change specific value of the column of csv file. For example I have csv file:
"Ip","Sites"
"127.0.0.1",10
"127.0.0.2",23
"127.0.0.3",50
and I need to change value 23 to 30 of the "127.0.0.2".
I use csv library: import csv
Appreciate any help as I'm new in Python. Thanks!
python csv filereader
asked Jun 14 '12 at 13:00
ihorko
3,570206198
I need the way to change specific value of the column of csv file. For example I have csv file:
"Ip","Sites"
"127.0.0.1",10
"127.0.0.2",23
"127.0.0.3",50
and I need to change value 23 to 30 of the "127.0.0.2".
I use csv library: import csv
Appreciate any help as I'm new in Python. Thanks!
python csv filereader
python csv filereader
asked Jun 14 '12 at 13:00
ihorko
3,570206198
asked Jun 14 '12 at 13:00
ihorko
3,570206198
asked Jun 14 '12 at 13:00
ihorko
3,570206198
asked Jun 14 '12 at 13:00
ihorko
3,570206198
asked Jun 14 '12 at 13:00
ihorko
3,570206198
3,570206198
So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13
add a comment |
So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13
So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13
add a comment |
3 Answers
3
active
oldest
votes
This is the solution opening the csv file, changing the values in memory and then writing back the changes to disk.
r = csv.reader(open('/tmp/test.csv')) # Here your csv file
lines = list(r)
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '23'],
['127.0.0.3', '50']]
Modifying the values:
lines[2][1] = '30'
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '30'],
['127.0.0.3', '50']]
Now we only have to write it back to a file
writer = csv.writer(open('/tmp/output.csv', 'w'))
writer.writerows(lines)
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:writer = csv.writer(open('/tmp/output.csv', 'wb'))
– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
add a comment |
You can't really replace values in the existing file. Instead, you need to:
- read in existing file
- alter file in memory
- write out new file (overwriting existing file)
What you can also do is read in the existing file line by line, writing it out to a new file, while replacing values on the fly. When done, close both files, delete the original and rename the new file.
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
add a comment |
You can use very powerful library called pandas. Here is the example.
import pandas as pd
df = pd.read_csv("test.csv")
df.head(3) #prints 3 heading rows
Output:
Ip Sites
0 127.0.0.1 10
1 127.0.0.2 23
2 127.0.0.3 50
Now if you want to change the value in the 'Sites' column in the 1st row, run:
df.set_value(1, "Sites", 30)
If you want to change all the values, where 'Ip' is equal to 127.0.0.2, run:
df.loc[df["Ip"]=="127.0.0.2", "Sites"] = 30
Finally, to save the values:
df.to_csv("test.csv", index=False)
answered Feb 21 '17 at 13:27
Yury
17.2k74676
1
Though it works for most of the time. Sometimes it givesPermissionError: [Errno 13] Permission denied: 'file.csv'Can you suspect what could be the reason?
– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
add a comment |
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3 Answers
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active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
This is the solution opening the csv file, changing the values in memory and then writing back the changes to disk.
r = csv.reader(open('/tmp/test.csv')) # Here your csv file
lines = list(r)
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '23'],
['127.0.0.3', '50']]
Modifying the values:
lines[2][1] = '30'
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '30'],
['127.0.0.3', '50']]
Now we only have to write it back to a file
writer = csv.writer(open('/tmp/output.csv', 'w'))
writer.writerows(lines)
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:writer = csv.writer(open('/tmp/output.csv', 'wb'))
– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
add a comment |
This is the solution opening the csv file, changing the values in memory and then writing back the changes to disk.
r = csv.reader(open('/tmp/test.csv')) # Here your csv file
lines = list(r)
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '23'],
['127.0.0.3', '50']]
Modifying the values:
lines[2][1] = '30'
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '30'],
['127.0.0.3', '50']]
Now we only have to write it back to a file
writer = csv.writer(open('/tmp/output.csv', 'w'))
writer.writerows(lines)
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:writer = csv.writer(open('/tmp/output.csv', 'wb'))
– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
add a comment |
This is the solution opening the csv file, changing the values in memory and then writing back the changes to disk.
r = csv.reader(open('/tmp/test.csv')) # Here your csv file
lines = list(r)
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '23'],
['127.0.0.3', '50']]
Modifying the values:
lines[2][1] = '30'
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '30'],
['127.0.0.3', '50']]
Now we only have to write it back to a file
writer = csv.writer(open('/tmp/output.csv', 'w'))
writer.writerows(lines)
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
This is the solution opening the csv file, changing the values in memory and then writing back the changes to disk.
r = csv.reader(open('/tmp/test.csv')) # Here your csv file
lines = list(r)
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '23'],
['127.0.0.3', '50']]
Modifying the values:
lines[2][1] = '30'
Content of lines:
[['Ip', 'Sites'],
['127.0.0.1', '10'],
['127.0.0.2', '30'],
['127.0.0.3', '50']]
Now we only have to write it back to a file
writer = csv.writer(open('/tmp/output.csv', 'w'))
writer.writerows(lines)
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
edited Jan 31 at 11:14
Aran-Fey
20.6k53368
20.6k53368
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
answered Jun 14 '12 at 13:15
Diego Navarro
6,31421725
6,31421725
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:writer = csv.writer(open('/tmp/output.csv', 'wb'))
– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
add a comment |
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:writer = csv.writer(open('/tmp/output.csv', 'wb'))
– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
1
1
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:
writer = csv.writer(open('/tmp/output.csv', 'wb'))– Nitay
Mar 4 '15 at 10:28
If you run into a double linebreak problem on the written csv, you might want to try openning the file as a binary:
writer = csv.writer(open('/tmp/output.csv', 'wb'))– Nitay
Mar 4 '15 at 10:28
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
Do you have to close the writer?
– pekasus
Jul 13 '17 at 13:57
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
You should close the file descriptor but not the writer. You can use "with" to manage files
– Diego Navarro
Jul 17 '17 at 9:56
add a comment |
You can't really replace values in the existing file. Instead, you need to:
- read in existing file
- alter file in memory
- write out new file (overwriting existing file)
What you can also do is read in the existing file line by line, writing it out to a new file, while replacing values on the fly. When done, close both files, delete the original and rename the new file.
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
add a comment |
You can't really replace values in the existing file. Instead, you need to:
- read in existing file
- alter file in memory
- write out new file (overwriting existing file)
What you can also do is read in the existing file line by line, writing it out to a new file, while replacing values on the fly. When done, close both files, delete the original and rename the new file.
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
add a comment |
You can't really replace values in the existing file. Instead, you need to:
- read in existing file
- alter file in memory
- write out new file (overwriting existing file)
What you can also do is read in the existing file line by line, writing it out to a new file, while replacing values on the fly. When done, close both files, delete the original and rename the new file.
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
You can't really replace values in the existing file. Instead, you need to:
- read in existing file
- alter file in memory
- write out new file (overwriting existing file)
What you can also do is read in the existing file line by line, writing it out to a new file, while replacing values on the fly. When done, close both files, delete the original and rename the new file.
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
answered Jun 14 '12 at 13:15
Daren Thomas
42.1k37130184
42.1k37130184
add a comment |
add a comment |
You can use very powerful library called pandas. Here is the example.
import pandas as pd
df = pd.read_csv("test.csv")
df.head(3) #prints 3 heading rows
Output:
Ip Sites
0 127.0.0.1 10
1 127.0.0.2 23
2 127.0.0.3 50
Now if you want to change the value in the 'Sites' column in the 1st row, run:
df.set_value(1, "Sites", 30)
If you want to change all the values, where 'Ip' is equal to 127.0.0.2, run:
df.loc[df["Ip"]=="127.0.0.2", "Sites"] = 30
Finally, to save the values:
df.to_csv("test.csv", index=False)
answered Feb 21 '17 at 13:27
Yury
17.2k74676
1
Though it works for most of the time. Sometimes it givesPermissionError: [Errno 13] Permission denied: 'file.csv'Can you suspect what could be the reason?
– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
add a comment |
You can use very powerful library called pandas. Here is the example.
import pandas as pd
df = pd.read_csv("test.csv")
df.head(3) #prints 3 heading rows
Output:
Ip Sites
0 127.0.0.1 10
1 127.0.0.2 23
2 127.0.0.3 50
Now if you want to change the value in the 'Sites' column in the 1st row, run:
df.set_value(1, "Sites", 30)
If you want to change all the values, where 'Ip' is equal to 127.0.0.2, run:
df.loc[df["Ip"]=="127.0.0.2", "Sites"] = 30
Finally, to save the values:
df.to_csv("test.csv", index=False)
answered Feb 21 '17 at 13:27
Yury
17.2k74676
1
Though it works for most of the time. Sometimes it givesPermissionError: [Errno 13] Permission denied: 'file.csv'Can you suspect what could be the reason?
– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
add a comment |
You can use very powerful library called pandas. Here is the example.
import pandas as pd
df = pd.read_csv("test.csv")
df.head(3) #prints 3 heading rows
Output:
Ip Sites
0 127.0.0.1 10
1 127.0.0.2 23
2 127.0.0.3 50
Now if you want to change the value in the 'Sites' column in the 1st row, run:
df.set_value(1, "Sites", 30)
If you want to change all the values, where 'Ip' is equal to 127.0.0.2, run:
df.loc[df["Ip"]=="127.0.0.2", "Sites"] = 30
Finally, to save the values:
df.to_csv("test.csv", index=False)
answered Feb 21 '17 at 13:27
Yury
17.2k74676
You can use very powerful library called pandas. Here is the example.
import pandas as pd
df = pd.read_csv("test.csv")
df.head(3) #prints 3 heading rows
Output:
Ip Sites
0 127.0.0.1 10
1 127.0.0.2 23
2 127.0.0.3 50
Now if you want to change the value in the 'Sites' column in the 1st row, run:
df.set_value(1, "Sites", 30)
If you want to change all the values, where 'Ip' is equal to 127.0.0.2, run:
df.loc[df["Ip"]=="127.0.0.2", "Sites"] = 30
Finally, to save the values:
df.to_csv("test.csv", index=False)
answered Feb 21 '17 at 13:27
Yury
17.2k74676
answered Feb 21 '17 at 13:27
Yury
17.2k74676
answered Feb 21 '17 at 13:27
Yury
17.2k74676
answered Feb 21 '17 at 13:27
Yury
17.2k74676
17.2k74676
1
Though it works for most of the time. Sometimes it givesPermissionError: [Errno 13] Permission denied: 'file.csv'Can you suspect what could be the reason?
– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
add a comment |
1
Though it works for most of the time. Sometimes it givesPermissionError: [Errno 13] Permission denied: 'file.csv'Can you suspect what could be the reason?
– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
1
1
Though it works for most of the time. Sometimes it gives
PermissionError: [Errno 13] Permission denied: 'file.csv' Can you suspect what could be the reason?– Guru
Mar 30 at 12:34
Though it works for most of the time. Sometimes it gives
PermissionError: [Errno 13] Permission denied: 'file.csv' Can you suspect what could be the reason?– Guru
Mar 30 at 12:34
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
This is not related to this code. It seems that you do not have write permissions to the file.
– Yury
Apr 3 at 6:42
add a comment |
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So, I can read from csv file and write to csv file, but I haven't an idea how to repace values in existing file...
– ihorko
Jun 14 '12 at 13:11
Could you post the read/write code that you already have? At some point you should have the data in Python and you can modify it there before writing.
– Simeon Visser
Jun 14 '12 at 13:13