CSV copy with pandas
I know this topic has been extensively treated, but I'm not able to get what I want, sorry about the probably newbie question. So the thing is I have a CSV like this:
Date,"Tmax","Tmin","Tmedia","Rachas","Vmax","LT","L1","L2","L3","L4"
23 nov 2018,"14.0 (15:30)","7.3 (23:59)","10.7","12 (14:50)","5 (14:50)","2.0","1.6","0.4","0.0","0.0"
I am getting a new CSV like that one each day, with multiple rows, but I'm interested only in the first row after the header. What I want to do is copying that first row each day to a new CSV iteratively, so at the end of the week, that CSV should have seven rows. Additionally, I'd like to check if that date is already in that daily file. The thing is that I'm not getting the new CSV right, here's my try:
import pandas as pd
df = pd.read_csv('file.csv', skiprows=4, header=None)
writer=df[df.index.isin([0])].to_csv('output.csv',header=None)
The problem with this code is that it overwrites the file output.csv each time. Then I considered changing it to:
writer=df[df.index.isin([0])]
pd.read_csv('output.csv').append(writer).to_csv('output.csv',header=None)
The problem now is that it does need the file to previously exist; and even so, the information is not correctly copied to the new file. I think it must be simpler than this, but I'm stuck. Thanks for your help.
python pandas csv
edited Nov 25 '18 at 1:36
jpp
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
add a comment |
I know this topic has been extensively treated, but I'm not able to get what I want, sorry about the probably newbie question. So the thing is I have a CSV like this:
Date,"Tmax","Tmin","Tmedia","Rachas","Vmax","LT","L1","L2","L3","L4"
23 nov 2018,"14.0 (15:30)","7.3 (23:59)","10.7","12 (14:50)","5 (14:50)","2.0","1.6","0.4","0.0","0.0"
I am getting a new CSV like that one each day, with multiple rows, but I'm interested only in the first row after the header. What I want to do is copying that first row each day to a new CSV iteratively, so at the end of the week, that CSV should have seven rows. Additionally, I'd like to check if that date is already in that daily file. The thing is that I'm not getting the new CSV right, here's my try:
import pandas as pd
df = pd.read_csv('file.csv', skiprows=4, header=None)
writer=df[df.index.isin([0])].to_csv('output.csv',header=None)
The problem with this code is that it overwrites the file output.csv each time. Then I considered changing it to:
writer=df[df.index.isin([0])]
pd.read_csv('output.csv').append(writer).to_csv('output.csv',header=None)
The problem now is that it does need the file to previously exist; and even so, the information is not correctly copied to the new file. I think it must be simpler than this, but I'm stuck. Thanks for your help.
python pandas csv
edited Nov 25 '18 at 1:36
jpp
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
add a comment |
I know this topic has been extensively treated, but I'm not able to get what I want, sorry about the probably newbie question. So the thing is I have a CSV like this:
Date,"Tmax","Tmin","Tmedia","Rachas","Vmax","LT","L1","L2","L3","L4"
23 nov 2018,"14.0 (15:30)","7.3 (23:59)","10.7","12 (14:50)","5 (14:50)","2.0","1.6","0.4","0.0","0.0"
I am getting a new CSV like that one each day, with multiple rows, but I'm interested only in the first row after the header. What I want to do is copying that first row each day to a new CSV iteratively, so at the end of the week, that CSV should have seven rows. Additionally, I'd like to check if that date is already in that daily file. The thing is that I'm not getting the new CSV right, here's my try:
import pandas as pd
df = pd.read_csv('file.csv', skiprows=4, header=None)
writer=df[df.index.isin([0])].to_csv('output.csv',header=None)
The problem with this code is that it overwrites the file output.csv each time. Then I considered changing it to:
writer=df[df.index.isin([0])]
pd.read_csv('output.csv').append(writer).to_csv('output.csv',header=None)
The problem now is that it does need the file to previously exist; and even so, the information is not correctly copied to the new file. I think it must be simpler than this, but I'm stuck. Thanks for your help.
python pandas csv
edited Nov 25 '18 at 1:36
jpp
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
I know this topic has been extensively treated, but I'm not able to get what I want, sorry about the probably newbie question. So the thing is I have a CSV like this:
Date,"Tmax","Tmin","Tmedia","Rachas","Vmax","LT","L1","L2","L3","L4"
23 nov 2018,"14.0 (15:30)","7.3 (23:59)","10.7","12 (14:50)","5 (14:50)","2.0","1.6","0.4","0.0","0.0"
I am getting a new CSV like that one each day, with multiple rows, but I'm interested only in the first row after the header. What I want to do is copying that first row each day to a new CSV iteratively, so at the end of the week, that CSV should have seven rows. Additionally, I'd like to check if that date is already in that daily file. The thing is that I'm not getting the new CSV right, here's my try:
import pandas as pd
df = pd.read_csv('file.csv', skiprows=4, header=None)
writer=df[df.index.isin([0])].to_csv('output.csv',header=None)
The problem with this code is that it overwrites the file output.csv each time. Then I considered changing it to:
writer=df[df.index.isin([0])]
pd.read_csv('output.csv').append(writer).to_csv('output.csv',header=None)
The problem now is that it does need the file to previously exist; and even so, the information is not correctly copied to the new file. I think it must be simpler than this, but I'm stuck. Thanks for your help.
python pandas csv
python pandas csv
edited Nov 25 '18 at 1:36
jpp
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
edited Nov 25 '18 at 1:36
jpp
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
edited Nov 25 '18 at 1:36
jpp
101k2164114
edited Nov 25 '18 at 1:36
jpp
101k2164114
edited Nov 25 '18 at 1:36
jpp
101k2164114
101k2164114
asked Nov 25 '18 at 1:26
amodeoamodeo
61
asked Nov 25 '18 at 1:26
amodeoamodeo
61
asked Nov 25 '18 at 1:26
amodeoamodeo
61
61
add a comment |
add a comment |
1 Answer
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If you only want the first row after the header, read the header and just use nrows=1. Then use open in append mode to write your one-row dataframe to the end of the csv file. The header=False argument deals nicely with excluding the header when writing.
df = pd.read_csv('file.csv', nrows=1)
with open('output.csv', 'a') as fout:
df.to_csv(fout, header=False)
I've omitted skiprows=4 because it's not clear how this relates to your input data.
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
add a comment |
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1 Answer
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active
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
If you only want the first row after the header, read the header and just use nrows=1. Then use open in append mode to write your one-row dataframe to the end of the csv file. The header=False argument deals nicely with excluding the header when writing.
df = pd.read_csv('file.csv', nrows=1)
with open('output.csv', 'a') as fout:
df.to_csv(fout, header=False)
I've omitted skiprows=4 because it's not clear how this relates to your input data.
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
add a comment |
If you only want the first row after the header, read the header and just use nrows=1. Then use open in append mode to write your one-row dataframe to the end of the csv file. The header=False argument deals nicely with excluding the header when writing.
df = pd.read_csv('file.csv', nrows=1)
with open('output.csv', 'a') as fout:
df.to_csv(fout, header=False)
I've omitted skiprows=4 because it's not clear how this relates to your input data.
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
add a comment |
If you only want the first row after the header, read the header and just use nrows=1. Then use open in append mode to write your one-row dataframe to the end of the csv file. The header=False argument deals nicely with excluding the header when writing.
df = pd.read_csv('file.csv', nrows=1)
with open('output.csv', 'a') as fout:
df.to_csv(fout, header=False)
I've omitted skiprows=4 because it's not clear how this relates to your input data.
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
If you only want the first row after the header, read the header and just use nrows=1. Then use open in append mode to write your one-row dataframe to the end of the csv file. The header=False argument deals nicely with excluding the header when writing.
df = pd.read_csv('file.csv', nrows=1)
with open('output.csv', 'a') as fout:
df.to_csv(fout, header=False)
I've omitted skiprows=4 because it's not clear how this relates to your input data.
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
answered Nov 25 '18 at 1:32
jppjpp
101k2164114
101k2164114
add a comment |
add a comment |
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