how to get the numbers of factors in a matrix

 
Dear friends,
 
 
I have a question do not know how to resolve.
 
 
I have a big matrix composed of different columns (I use N here).  
A column is "species" and another one is "latitudes". Now, I want  
to know how I can get the number of different "latitudes" for every  
"species". I have tried to split the matrix according to species  
(X<-split(N, N$species) and then use sapply(X, function(m){nlevels(m$latitudes)})  
to get that. But the result shows the total factor numbers of "latitudes"  
but not the factor numbers of every species I splitted. Also,  
I have tried to use tapply(N$latitudes, N$species, nlevels)  
to do this. The result is the same. I am confused about this. Can  
someone help me with that? Thank you very much!
 
 
Best regards,
Yichun
 
 
 
 
 
 
[[alternative HTML version deleted]]
 

ff<-factor(letters[1:5])
levels(ff[1:2])

fff<-ff[1:2]
nlevels(fff)

fff

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of ???
Sent: Tuesday, January 21, 2014 7:36 AM
To: r-help at r-project.org
Subject: [R] how to get the numbers of factors in a matrix

Dear friends,


I have a question do not know how to resolve.


I have a big matrix composed of different columns (I use N here). A
column is "species" and another one is "latitudes". Now, I want to know
how I can get the number of different "latitudes" for every "species".
I have tried to split the matrix according to species (X<-split(N,
N$species) and then use sapply(X, function(m){nlevels(m$latitudes)}) to
get that. But the result shows the total factor numbers of "latitudes"
but not the factor numbers of every species I splitted. Also, I have
tried to use tapply(N$latitudes, N$species, nlevels) to do this. The
result is the same. I am confused about this. Can someone help me with
that? Thank you very much!


Best regards,
Yichun






      [[alternative HTML version deleted]]

Dear Pikal,


Thank you very much for your answer. 


I think your example is just the problem I have. 


In the following example you gave to me, 

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

In my understanding, fff is a subset of ff. Why fff's levels is not "a,
b" but "a,b,c,d,e".


My problem is quite similar to the example. I just want to split the
matrix into many subsets and calculate the levels of every subset. Can
you tell me how to do? Thank you very much!


Best regards,
Yichun

-----????????????-----
?????????: "PIKAL Petr" <petr.pikal at precheza.cz>
????????????: 2014???1???21??? ?????????
?????????: "?????????" <yczhang at nigpas.ac.cn>, "r-help at r-project.org"

<r-help at r-project.org>

??????: 
??????: RE: [R] how to get the numbers of factors in a matrix

Hi

It is rather difficult to understand what problem you have.

post some data e.g. by

dput(head(bigmatrix))

Maybe your problem is in a factor feature that it preserves also

empty levels until you specifically drop them.

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

Regards
Petr

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of ???
Sent: Tuesday, January 21, 2014 7:36 AM
To: r-help at r-project.org
Subject: [R] how to get the numbers of factors in a matrix

Dear friends,


I have a question do not know how to resolve.


I have a big matrix composed of different columns (I use N here). A
column is "species" and another one is "latitudes". Now, I want to

know

how I can get the number of different "latitudes" for every

"species".

I have tried to split the matrix according to species (X<-split(N,
N$species) and then use sapply(X,

function(m){nlevels(m$latitudes)}) to

get that. But the result shows the total factor numbers of

"latitudes"

but not the factor numbers of every species I splitted. Also, I

have

tried to use tapply(N$latitudes, N$species, nlevels) to do this.

The

result is the same. I am confused about this. Can someone help me

with

that? Thank you very much!


Best regards,
Yichun






      [[alternative HTML version deleted]]

d??v??rn?? a jsou ur??eny pouze jeho adres??t??m.

Jestli??e jste obdr??el(a) tento e-mail omylem, informujte laskav??

neprodlen?? jeho odes??latele. Obsah tohoto emailu i s p????lohami a
jeho kopie vyma??te ze sv??ho syst??mu.

Nejste-li zam????len??m adres??tem tohoto emailu, nejste opr??vn??ni

tento email jakkoliv u????vat, roz??i??ovat, kop??rovat ??i
zve??ej??ovat.

Odes??latel e-mailu neodpov??d?? za eventu??ln?? ??kodu zp??sobenou

modifikacemi ??i zpo??d??n??m p??enosu e-mailu.

V p????pad??, ??e je tento e-mail sou????st?? obchodn??ho jedn??n??:
- vyhrazuje si odes??latel pr??vo ukon??it kdykoliv jedn??n?? o

uzav??en?? smlouvy, a to z jak??hokoliv d??vodu i bez uveden?? d??vodu.

- a obsahuje-li nab??dku, je adres??t opr??vn??n nab??dku

bezodkladn?? p??ijmout; Odes??latel tohoto e-mailu (nab??dky) vylu??uje
p??ijet?? nab??dky ze strany p????jemce s dodatkem ??i odchylkou.

- trv?? odes??latel na tom, ??e p????slu??n?? smlouva je uzav??ena

teprve v??slovn??m dosa??en??m shody na v??ech jej??ch n??le??itostech.

- odes??latel tohoto emailu informuje, ??e nen?? opr??vn??n uzav??rat

za spole??nost ????dn?? smlouvy s v??jimkou p????pad??, kdy k tomu byl
p??semn?? zmocn??n nebo p??semn?? pov????en a takov?? pov????en?? nebo
pln?? moc byly adres??tovi tohoto emailu p????padn?? osob??, kterou
adres??t zastupuje, p??edlo??eny nebo jejich existence je adres??tovi
??i osob?? j??m zastoupen?? zn??m??.

This e-mail and any documents attached to it may be confidential and

are intended only for its intended recipients.

If you received this e-mail by mistake, please immediately inform its

sender. Delete the contents of this e-mail with all attachments and its
copies from your system.

If you are not the intended recipient of this e-mail, you are not

authorized to use, disseminate, copy or disclose this e-mail in any
manner.

The sender of this e-mail shall not be liable for any possible damage

caused by modifications of the e-mail or by delay with transfer of the
email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering

into a contract in any time, for any reason, and without stating any
reasoning.

- if the e-mail contains an offer, the recipient is entitled to

immediately accept such offer; The sender of this e-mail (offer)
excludes any acceptance of the offer on the part of the recipient
containing any amendment or variation.

- the sender insists on that the respective contract is concluded

only upon an express mutual agreement on all its aspects.

- the sender of this e-mail informs that he/she is not authorized to

enter into any contracts on behalf of the company except for cases in
which he/she is expressly authorized to do so in writing, and such
authorization or power of attorney is submitted to the recipient or the
person represented by the recipient, or the existence of such
authorization is known to the recipient of the person represented by
the recipient.



--
Dr Yichun Zhang
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing
Institute of Geology and Palaeontology
39 East Beijing Road, Nanjing, China, 210008




[[alternative HTML version deleted]]



------------------------------------------------------------------------

You are mis-using factors. Would you pretend that women do not exist just because your sample happens to include only men?

If you really need to ignore those other levels, convert your factor to character and summarize those values.

sapply(X, function(m){nlevels(factor(m$latitudes))})

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of PIKAL Petr
Sent: Tuesday, January 21, 2014 11:29 PM
To: ???
Cc: r-help at r-project.org
Subject: Re: [R] how to get the numbers of factors in a matrix

Hi

elaborating answers you already got

sapply(X, function(m){nlevels(factor(m$latitudes))})
tapply(N$latitudes, N$species, function(x) nlevels(factor(x)))

shall do the trick

Petr

From: ??? [mailto:yczhang at nigpas.ac.cn]
Sent: Tuesday, January 21, 2014 2:58 PM
To: PIKAL Petr
Cc: r-help at r-project.org
Subject: Re: RE: [R] how to get the numbers of factors in a matrix

Dear Pikal,

Thank you very much for your answer.

I think your example is just the problem I have.

In the following example you gave to me,

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

In my understanding, fff is a subset of ff. Why fff's levels is not "a, b" but "a,b,c,d,e".

My problem is quite similar to the example. I just want to split the matrix into many
subsets and calculate the levels of every subset. Can you tell me how to do? Thank you
very much!

Best regards,
Yichun

-----????-----
???: "PIKAL Petr" <petr.pikal at precheza.cz<mailto:petr.pikal at precheza.cz>>
????: 2014?1?21? ???
???: "???" <yczhang at nigpas.ac.cn<mailto:yczhang at nigpas.ac.cn>>, "r-

help at r-project.org<mailto:r-help at r-project.org>" <r-help at r-project.org<mailto:r-
help at r-project.org>>

??:
??: RE: [R] how to get the numbers of factors in a matrix

Hi

It is rather difficult to understand what problem you have.

post some data e.g. by

dput(head(bigmatrix))

Maybe your problem is in a factor feature that it preserves also empty levels until you

specifically drop them.

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

Regards
Petr

-----Original Message-----
From: r-help-bounces at r-project.org<mailto:r-help-bounces at r-project.org>

[mailto:r-help-bounces at r-

project.org<mailto:r-help-bounces at r-%0b%3e?%3e?project.org>] On Behalf Of ???
Sent: Tuesday, January 21, 2014 7:36 AM
To: r-help at r-project.org<mailto:r-help at r-project.org>
Subject: [R] how to get the numbers of factors in a matrix

Dear friends,


I have a question do not know how to resolve.


I have a big matrix composed of different columns (I use N here). A
column is "species" and another one is "latitudes". Now, I want to know
how I can get the number of different "latitudes" for every "species".
I have tried to split the matrix according to species (X<-split(N,
N$species) and then use sapply(X, function(m){nlevels(m$latitudes)}) to
get that. But the result shows the total factor numbers of "latitudes"
but not the factor numbers of every species I splitted. Also, I have
tried to use tapply(N$latitudes, N$species, nlevels) to do this. The
result is the same. I am confused about this. Can someone help me with
that? Thank you very much!


Best regards,
Yichun






      [[alternative HTML version deleted]]

jeho adres?t?m.

Jestli?e jste obdr?el(a) tento e-mail omylem, informujte laskav? neprodlen? jeho

odes?latele. Obsah tohoto emailu i s p??lohami a jeho kopie vyma?te ze sv?ho syst?mu.

Nejste-li zam??len?m adres?tem tohoto emailu, nejste opr?vn?ni tento email jakkoliv

u??vat, roz?i?ovat, kop?rovat ?i zve?ej?ovat.

Odes?latel e-mailu neodpov?d? za eventu?ln? ?kodu zp?sobenou modifikacemi ?i

zpo?d?n?m p?enosu e-mailu.

V p??pad?, ?e je tento e-mail sou??st? obchodn?ho jedn?n?:
- vyhrazuje si odes?latel pr?vo ukon?it kdykoliv jedn?n? o uzav?en? smlouvy, a to z

jak?hokoliv d?vodu i bez uveden? d?vodu.

- a obsahuje-li nab?dku, je adres?t opr?vn?n nab?dku bezodkladn? p?ijmout; Odes?latel

tohoto e-mailu (nab?dky) vylu?uje p?ijet? nab?dky ze strany p??jemce s dodatkem ?i
odchylkou.

- trv? odes?latel na tom, ?e p??slu?n? smlouva je uzav?ena teprve v?slovn?m dosa?en?m

shody na v?ech jej?ch n?le?itostech.

- odes?latel tohoto emailu informuje, ?e nen? opr?vn?n uzav?rat za spole?nost ??dn?

smlouvy s v?jimkou p??pad?, kdy k tomu byl p?semn? zmocn?n nebo p?semn? pov??en a
takov? pov??en? nebo pln? moc byly adres?tovi tohoto emailu p??padn? osob?, kterou
adres?t zastupuje, p?edlo?eny nebo jejich existence je adres?tovi ?i osob? j?m zastoupen?
zn?m?.

This e-mail and any documents attached to it may be confidential and are intended only

for its intended recipients.

If you received this e-mail by mistake, please immediately inform its sender. Delete the

contents of this e-mail with all attachments and its copies from your system.

If you are not the intended recipient of this e-mail, you are not authorized to use,

disseminate, copy or disclose this e-mail in any manner.

The sender of this e-mail shall not be liable for any possible damage caused by

modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a contract in any

time, for any reason, and without stating any reasoning.

- if the e-mail contains an offer, the recipient is entitled to immediately accept such

offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part
of the recipient containing any amendment or variation.

- the sender insists on that the respective contract is concluded only upon an express

mutual agreement on all its aspects.

- the sender of this e-mail informs that he/she is not authorized to enter into any

contracts on behalf of the company except for cases in which he/she is expressly
authorized to do so in writing, and such authorization or power of attorney is submitted
to the recipient or the person represented by the recipient, or the existence of such
authorization is known to the recipient of the person represented by the recipient.



--
Dr Yichun Zhang
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and
Palaeontology
39 East Beijing Road, Nanjing, China, 210008

sapply(X, function(m){nlevels(factor(m$latitudes))})

I think that length(unique(x)) is a more direct and easier to remember
way of determining the number of unique values in the vector x,
rather than nlevels(factor(x)).

length(unique(factor(c(1,2,NA))))

nlevels(factor(c(1,2,NA)))

Bill Dunlap
TIBCO Software
wdunlap tibco.com

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
Of PIKAL Petr
Sent: Tuesday, January 21, 2014 11:29 PM
To: ???
Cc: r-help at r-project.org
Subject: Re: [R] how to get the numbers of factors in a matrix

Hi

elaborating answers you already got

sapply(X, function(m){nlevels(factor(m$latitudes))})
tapply(N$latitudes, N$species, function(x) nlevels(factor(x)))

shall do the trick

Petr

From: ??? [mailto:yczhang at nigpas.ac.cn]
Sent: Tuesday, January 21, 2014 2:58 PM
To: PIKAL Petr
Cc: r-help at r-project.org
Subject: Re: RE: [R] how to get the numbers of factors in a matrix

Dear Pikal,

Thank you very much for your answer.

I think your example is just the problem I have.

In the following example you gave to me,

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

In my understanding, fff is a subset of ff. Why fff's levels is not "a, b" but "a,b,c,d,e".

My problem is quite similar to the example. I just want to split the matrix into many
subsets and calculate the levels of every subset. Can you tell me how to do? Thank you
very much!

Best regards,
Yichun

-----????-----
???: "PIKAL Petr" <petr.pikal at precheza.cz<mailto:petr.pikal at precheza.cz>>
????: 2014?1?21? ???
???: "???" <yczhang at nigpas.ac.cn<mailto:yczhang at nigpas.ac.cn>>, "r-

help at r-project.org<mailto:r-help at r-project.org>" <r-help at r-project.org<mailto:r-
help at r-project.org>>

??:
??: RE: [R] how to get the numbers of factors in a matrix

Hi

It is rather difficult to understand what problem you have.

post some data e.g. by

dput(head(bigmatrix))

Maybe your problem is in a factor feature that it preserves also empty levels until you

specifically drop them.

ff<-factor(letters[1:5])
levels(ff[1:2])

[1] "a" "b" "c" "d" "e"

fff<-ff[1:2]
nlevels(fff)

[1] 5

fff

[1] a b
Levels: a b c d e

Regards
Petr

-----Original Message-----
From: r-help-bounces at r-project.org<mailto:r-help-bounces at r-project.org>

[mailto:r-help-bounces at r-

project.org<mailto:r-help-bounces at r-%0b%3e %3e project.org>] On Behalf Of ???
Sent: Tuesday, January 21, 2014 7:36 AM
To: r-help at r-project.org<mailto:r-help at r-project.org>
Subject: [R] how to get the numbers of factors in a matrix

Dear friends,


I have a question do not know how to resolve.


I have a big matrix composed of different columns (I use N here). A
column is "species" and another one is "latitudes". Now, I want to know
how I can get the number of different "latitudes" for every "species".
I have tried to split the matrix according to species (X<-split(N,
N$species) and then use sapply(X, function(m){nlevels(m$latitudes)}) to
get that. But the result shows the total factor numbers of "latitudes"
but not the factor numbers of every species I splitted. Also, I have
tried to use tapply(N$latitudes, N$species, nlevels) to do this. The
result is the same. I am confused about this. Can someone help me with
that? Thank you very much!


Best regards,
Yichun






     [[alternative HTML version deleted]]

jeho adres?t?m.

Jestli?e jste obdr?el(a) tento e-mail omylem, informujte laskav? neprodlen? jeho

odes?latele. Obsah tohoto emailu i s p??lohami a jeho kopie vyma?te ze sv?ho syst?mu.

Nejste-li zam??len?m adres?tem tohoto emailu, nejste opr?vn?ni tento email jakkoliv

u??vat, roz?i?ovat, kop?rovat ?i zve?ej?ovat.

Odes?latel e-mailu neodpov?d? za eventu?ln? ?kodu zp?sobenou modifikacemi ?i

zpo?d?n?m p?enosu e-mailu.

V p??pad?, ?e je tento e-mail sou??st? obchodn?ho jedn?n?:
- vyhrazuje si odes?latel pr?vo ukon?it kdykoliv jedn?n? o uzav?en? smlouvy, a to z

jak?hokoliv d?vodu i bez uveden? d?vodu.

- a obsahuje-li nab?dku, je adres?t opr?vn?n nab?dku bezodkladn? p?ijmout; Odes?latel

tohoto e-mailu (nab?dky) vylu?uje p?ijet? nab?dky ze strany p??jemce s dodatkem ?i
odchylkou.

- trv? odes?latel na tom, ?e p??slu?n? smlouva je uzav?ena teprve v?slovn?m dosa?en?m

shody na v?ech jej?ch n?le?itostech.

- odes?latel tohoto emailu informuje, ?e nen? opr?vn?n uzav?rat za spole?nost ??dn?

smlouvy s v?jimkou p??pad?, kdy k tomu byl p?semn? zmocn?n nebo p?semn? pov??en a
takov? pov??en? nebo pln? moc byly adres?tovi tohoto emailu p??padn? osob?, kterou
adres?t zastupuje, p?edlo?eny nebo jejich existence je adres?tovi ?i osob? j?m zastoupen?
zn?m?.

This e-mail and any documents attached to it may be confidential and are intended only

for its intended recipients.

If you received this e-mail by mistake, please immediately inform its sender. Delete the

contents of this e-mail with all attachments and its copies from your system.

If you are not the intended recipient of this e-mail, you are not authorized to use,

disseminate, copy or disclose this e-mail in any manner.

The sender of this e-mail shall not be liable for any possible damage caused by

modifications of the e-mail or by delay with transfer of the email.

In case that this e-mail forms part of business dealings:
- the sender reserves the right to end negotiations about entering into a contract in any

time, for any reason, and without stating any reasoning.

- if the e-mail contains an offer, the recipient is entitled to immediately accept such

offer; The sender of this e-mail (offer) excludes any acceptance of the offer on the part
of the recipient containing any amendment or variation.

- the sender insists on that the respective contract is concluded only upon an express

mutual agreement on all its aspects.

- the sender of this e-mail informs that he/she is not authorized to enter into any

contracts on behalf of the company except for cases in which he/she is expressly
authorized to do so in writing, and such authorization or power of attorney is submitted
to the recipient or the person represented by the recipient, or the existence of such
authorization is known to the recipient of the person represented by the recipient.



--
Dr Yichun Zhang
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and
Palaeontology
39 East Beijing Road, Nanjing, China, 210008