Filling missing values in dataframe column Python
1
My data is broken up into 4 columns and looks like:
State Year Month Value
AK 2010 1 10
AK 2010 3 20
AK 2011 1 28
AK 2011 5 29
AK 2011 12 31
.
.
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 12 22
TX 2011 4 30
TX 2011 7 33
.
.
I want to fill the missing Months with repetitions of the previous Values of the same Year because they are just cumulative sums that I've added together.
The months do not always begin back at Month 1 and sometimes can be missing full years so I need to address this.
Ie: TX can start at Month 4 in 2011 etc...
The desired output looks like:
State Year Month Value
AK 2010 1 10
AK 2010 2 10
AK 2010 3 20
AK 2010 4 20
AK 2010 5 20
.
.
AK 2010 12 20
AK 2011 1 28
AK 2011 2 28
.
.
TX 2010 1 9
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 5 20
.
.
TX 2010 12 22
python python-3.x pandas dataframe
asked Nov 11 at 0:14
HelloToEarth
370210
add a comment |Â
1
My data is broken up into 4 columns and looks like:
State Year Month Value
AK 2010 1 10
AK 2010 3 20
AK 2011 1 28
AK 2011 5 29
AK 2011 12 31
.
.
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 12 22
TX 2011 4 30
TX 2011 7 33
.
.
I want to fill the missing Months with repetitions of the previous Values of the same Year because they are just cumulative sums that I've added together.
The months do not always begin back at Month 1 and sometimes can be missing full years so I need to address this.
Ie: TX can start at Month 4 in 2011 etc...
The desired output looks like:
State Year Month Value
AK 2010 1 10
AK 2010 2 10
AK 2010 3 20
AK 2010 4 20
AK 2010 5 20
.
.
AK 2010 12 20
AK 2011 1 28
AK 2011 2 28
.
.
TX 2010 1 9
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 5 20
.
.
TX 2010 12 22
python python-3.x pandas dataframe
asked Nov 11 at 0:14
HelloToEarth
370210
Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
1
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25
add a comment |Â
1
1
1
My data is broken up into 4 columns and looks like:
State Year Month Value
AK 2010 1 10
AK 2010 3 20
AK 2011 1 28
AK 2011 5 29
AK 2011 12 31
.
.
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 12 22
TX 2011 4 30
TX 2011 7 33
.
.
I want to fill the missing Months with repetitions of the previous Values of the same Year because they are just cumulative sums that I've added together.
The months do not always begin back at Month 1 and sometimes can be missing full years so I need to address this.
Ie: TX can start at Month 4 in 2011 etc...
The desired output looks like:
State Year Month Value
AK 2010 1 10
AK 2010 2 10
AK 2010 3 20
AK 2010 4 20
AK 2010 5 20
.
.
AK 2010 12 20
AK 2011 1 28
AK 2011 2 28
.
.
TX 2010 1 9
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 5 20
.
.
TX 2010 12 22
python python-3.x pandas dataframe
asked Nov 11 at 0:14
HelloToEarth
370210
My data is broken up into 4 columns and looks like:
State Year Month Value
AK 2010 1 10
AK 2010 3 20
AK 2011 1 28
AK 2011 5 29
AK 2011 12 31
.
.
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 12 22
TX 2011 4 30
TX 2011 7 33
.
.
I want to fill the missing Months with repetitions of the previous Values of the same Year because they are just cumulative sums that I've added together.
The months do not always begin back at Month 1 and sometimes can be missing full years so I need to address this.
Ie: TX can start at Month 4 in 2011 etc...
The desired output looks like:
State Year Month Value
AK 2010 1 10
AK 2010 2 10
AK 2010 3 20
AK 2010 4 20
AK 2010 5 20
.
.
AK 2010 12 20
AK 2011 1 28
AK 2011 2 28
.
.
TX 2010 1 9
TX 2010 2 10
TX 2010 3 11
TX 2010 4 20
TX 2010 5 20
.
.
TX 2010 12 22
python python-3.x pandas dataframe
python python-3.x pandas dataframe
asked Nov 11 at 0:14
HelloToEarth
370210
asked Nov 11 at 0:14
HelloToEarth
370210
edited Nov 11 at 1:32
asked Nov 11 at 0:14
HelloToEarth
370210
asked Nov 11 at 0:14
HelloToEarth
370210
asked Nov 11 at 0:14
HelloToEarth
370210
370210
Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
1
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25
add a comment |Â
Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
1
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25
Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
1
1
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25
add a comment |Â
1 Answer
1
active
oldest
votes
1
One solution is to use Categorical Data:
# convert Month to categorical with 1-12 range
df['Month'] = pd.Categorical(df['Month'], categories=range(1, 13))
# groupby to give Cartesian product for categorical columns
df = df.groupby(['State', 'Year', 'Month']).first().reset_index()
# forward fill by group
df['Value'] = df.groupby('State')['Value'].ffill()
This solution assumes Dec-2010 data can spill over to null data for Jan-2011 for a particular state.
answered Nov 11 at 0:28
jpp
91k2052102
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
1
One solution is to use Categorical Data:
# convert Month to categorical with 1-12 range
df['Month'] = pd.Categorical(df['Month'], categories=range(1, 13))
# groupby to give Cartesian product for categorical columns
df = df.groupby(['State', 'Year', 'Month']).first().reset_index()
# forward fill by group
df['Value'] = df.groupby('State')['Value'].ffill()
This solution assumes Dec-2010 data can spill over to null data for Jan-2011 for a particular state.
answered Nov 11 at 0:28
jpp
91k2052102
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
add a comment |Â
1
One solution is to use Categorical Data:
# convert Month to categorical with 1-12 range
df['Month'] = pd.Categorical(df['Month'], categories=range(1, 13))
# groupby to give Cartesian product for categorical columns
df = df.groupby(['State', 'Year', 'Month']).first().reset_index()
# forward fill by group
df['Value'] = df.groupby('State')['Value'].ffill()
This solution assumes Dec-2010 data can spill over to null data for Jan-2011 for a particular state.
answered Nov 11 at 0:28
jpp
91k2052102
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
add a comment |Â
1
1
1
One solution is to use Categorical Data:
# convert Month to categorical with 1-12 range
df['Month'] = pd.Categorical(df['Month'], categories=range(1, 13))
# groupby to give Cartesian product for categorical columns
df = df.groupby(['State', 'Year', 'Month']).first().reset_index()
# forward fill by group
df['Value'] = df.groupby('State')['Value'].ffill()
This solution assumes Dec-2010 data can spill over to null data for Jan-2011 for a particular state.
answered Nov 11 at 0:28
jpp
91k2052102
One solution is to use Categorical Data:
# convert Month to categorical with 1-12 range
df['Month'] = pd.Categorical(df['Month'], categories=range(1, 13))
# groupby to give Cartesian product for categorical columns
df = df.groupby(['State', 'Year', 'Month']).first().reset_index()
# forward fill by group
df['Value'] = df.groupby('State')['Value'].ffill()
This solution assumes Dec-2010 data can spill over to null data for Jan-2011 for a particular state.
answered Nov 11 at 0:28
jpp
91k2052102
answered Nov 11 at 0:28
jpp
91k2052102
answered Nov 11 at 0:28
jpp
91k2052102
answered Nov 11 at 0:28
jpp
91k2052102
91k2052102
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
add a comment |Â
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
I actually have a strange nan issue. I've posted a screenshot above. Looks like it's not picking up previous years at times but it's because of what you had mentioned. Is there a way to spill over previous years?
– HelloToEarth
Nov 11 at 1:16
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
@HelloToEarth, Unfortunately, I can't replicate without a Minimal, Complete, and Verifiable example. See How to make good reproducible pandas examples if you need help with this (images / links don't help).
– jpp
Nov 11 at 1:21
add a comment |Â
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Do you need the same Year - Month span for each state? Or are they separate for each state?
– ALollz
Nov 11 at 0:21
1
Will every sequence begin with 1 always?
– coldspeed
Nov 11 at 0:23
They differ from State to State (AK may start at 1980 but TX or LA can start in 1991) but I need each Year to span the full 12 months for every State.
– HelloToEarth
Nov 11 at 0:23
Good question, @coldspeed. They do not begin at 1 always but I need them filled from the last month's value and automatically fill each from 1-12. I have changed my question to better address this.
– HelloToEarth
Nov 11 at 0:25