1. Install aspera download from http://downloads.asperasoft.com/downloads (select aspera connect and then show all installers) 2. Download using aspera working exampole download gtex to tarbell 11/25/214 (this didn’t work, cri-syncmon.cri.uchicago.edu may work) "/home/him1/.aspera/connect/bin/ascp" -QTr -l 300M -k 1 -i "/home/him1/.aspera/connect/etc/asperaweb_id_dsa.openssh" -W AB6D9CB19B62747EC89082FF7954E5F901C737E21A8D44CC3B2D4D2E94D0AA1E7C79C059D9E704B36AF81B523E9EA81C4D dbtest@gap-upload.ncbi.nlm.nih.gov:data/instant/haeky2/41316 . 3. download manifest 4. get repository key 5. Decrypt (modified on 4/15/2015) - download decryption tools from dbGaP - run ./vdb-config -i from the sratoolkit bin directory - press 4 and import repository key (prj_6981.ngc, this will create a working folder /Users/haky/ncbi/dbGaP-6981/) - from the working directory created by the ugly vdb-config run vbd-decrypt > cd /Users/haky/ncbi/dbGaP-6981/ > ~/bin/sratoolkit.2.4.5-2-mac64/bin/vdb-decrypt /Volumes/Pegasus/im-lab/nas40t2/haky/Data/dbGaP/GTEx/43830 working examples: 5052 is the number of the project that requested the data access (5052=Phenotype Prediction IRB) 43831 is the download request id
>cd /Users/haky/ncbi/dbGaP-5052/ >~/bin/sratoolkit.2.4.5-2-mac64/bin/vdb-decrypt /Volumes/Pegasus/im-lab/nas40t2/Data/dbGaP/Framingham/44795/
I should clean it up but the instructions on decrypting were helpful.
Thursday, July 23, 2015
Saturday, October 4, 2014
Wednesday, August 27, 2014
Sunday, August 24, 2014
Tuesday, August 19, 2014
Friday, July 11, 2014
Adding letter head to latex file
\documentclass{article} \usepackage{wallpaper} \ULCornerWallPaper{1}{letterheadfile.pdf} \begin{document} Your text on the letterhead \end{document} via http://tex.stackexchange.com/questions/837/pdf-letterhead-as-document-background
Thursday, July 3, 2014
Tuesday, July 1, 2014
R script to query UCSC database - RMySQL
## this will let you install R packages in a directory where you have access .libPaths('~/Rlibs/') ## create directory ~/Rlibs if it doesnt exist install.packages(RMySQL) ## call the RMySQL library library(RMySQL) ## connect to UCSC server channel = dbConnect(MySQL(), user="genome", host="genome-mysql.cse.ucsc.edu") ## for a list of tables check url below ## http://hgdownload.cse.ucsc.edu/goldenPath/hg19/database/ ## convenience function to run SQL queries query <- function(...) dbGetQuery(channel, ...) ## use hg19 database in UCSC to use query("USE hg19") ## see table content query("DESCRIBE snpArrayAffy5") ## get number of rows from table print( query("select count(*) from snpArrayAffy6") ) ## get number of rows from table tempo6 = query("select * from snpArrayAffy6")
Thursday, June 26, 2014
Tuesday, June 24, 2014
Statistical Genetics/Genomics Intro Material
http://genomicsclass.github.io/book/ (On github by Rafael Irizarry and Michael Love) http://www.ploscompbiol.org/article/info%3Adoi%2F10.1371%2Fjournal.pcbi.1002822 http://www.ploscollections.org/article/browseIssue.action?issue=info:doi/10.1371/issue.pcol.v03.i11 http://www.nature.com/nrg/series/gwas/index.html Data analysis for genomics https://www.edx.org/course/harvardx/harvardx-ph525x-data-analysis-genomics-1401#.U6m5uxappuY Python https://www.coursera.org/course/pythonlearn http://www.mooc-list.com/course/6001x-introduction-computer-science-and-programming-using-python-edx Linux Basic Commands https://wiki.uchicago.edu/display/CRIwksp/Introduction+to+Linux+Command+Line+for+Bioinformatics R intro UCLA http://www.ats.ucla.edu/stat/r/seminars/intro.htm R Basic Vocabulary http://adv-r.had.co.nz/Vocabulary.html Coursera Data Specialization Courses http://gettinggeneticsdone.blogspot.com/2014/01/coursera-specializations-data-science.html
Friday, June 20, 2014
Inverse normalization function
my.invnorm = function(x) { res = rank(x) res = qnorm(res/(length(res)+0.5)) return(res) }
Thursday, May 15, 2014
drop repeated vars keeping first row for given var
## function ## drop repeated vars but keeping first row for given var droprep = function(df,repvar,sortvar) { tab = table(df[,repvar]) nametab = names(tab) uniquelist = nametab[tab==1] replist = nametab[tab>1] ind = df[,repvar] %in% uniquelist res = df[ind,] tempo = df[!ind,] tempo = tempo[order(tempo[,sortvar]),] for(vv in replist) { rowa = tempo[tempo[,repvar]==vv,][1,] res = rbind(res,rowa) } return(res) }
Monday, March 24, 2014
How to create MySQL database with Entrez Gene Database Description and Files
http://jura.wi.mit.edu/entrez_gene/ "Entrez Gene is NCBI's repository for gene-specific information. Access to this information either through the Entrez Gene website or by flat files via NCBI's ftp site can be time consuming and limiting in regards to the number of and what questions you can ask about the data. A better solution for intense data mining is to create a relational database. We offer our MySQL based database and data loading script as an easy-to-implement solution to this problem. While the ER diagram describes the database we created, we also offer the SQL syntax for both the tables and indexes. The data loading script, which is written in Perl, will automatically download Entrez Gene data files, parse the data and load it into the MySQL database."
Sunday, March 23, 2014
Thursday, March 20, 2014
Tuesday, March 18, 2014
Thursday, March 6, 2014
How to start shiny application
Fire up R/RStudio, make sure you have the shiny package installed, and type library(shiny) runApp('~/vcs/rcg/haky') where you replace '~/vcs/rcg/haky' with the path to the directory containing the ui.R, server.R and screen.tiff files, and the data subdirectory. It should fire right up; you can then stop it by sending R an interrupt.
Monday, February 24, 2014
How to post R packages on cran
Here's the procedure for reference: upload the .tar.gz file, using ‘anonymous’ as log-in name and your e-mail address as password, to ftp://CRAN.R-project.org/incoming/ (note: use ‘ftp’ and not ‘sftp’ to connect to this server, and passive ‘ftp’ is more often successful) and send a message to CRAN@R-project.org about it (with your package name and version in the subject line of the form “CRAN submission package version”, and please do not submit a package by email). For a new submission, please note in the message that you have read and agreed to the CRAN policies.
Wednesday, February 19, 2014
How to access dbgap authorized files
As of 2/19/2014, I could log in directly through https://dbgap.ncbi.nlm.nih.gov/ using the Era Commons ID
Before I had to do the following steps
1. Log into Era Commons
https://public.era.nih.gov/(you need an Era Commons ID)
2. Goto https://dbgap.ncbi.nlm.nih.gov/
3. Click log in
You should be in then.
Tuesday, July 24, 2012
Friday, April 20, 2012
python script to convert plink bed/bim to qtdt format
import os sdir = '/hapmap/' basebedname = 'hapmap3' ddir = '/erlotinib/' temponame = 'tempo' phenoname = 'erlotinib' os.system('plink --bfile ' + sdir + basebedname + ' --recode12 --out ' + ddir + temponame ) ## join tempo.ped with phenodata.txt ## and generate pheno.ped file shortfilename = ddir + "phenodata.txt" ## FID,IID,dad,mom,sex,pheno1,... longfilename = ddir + temponame + ".ped" ## FID,IID,dad,mom,sex,pheno,snp1,... outfilename = ddir + phenoname + ".ped" index = {} shortfile= open( shortfilename, "r" ) for row in shortfile: part = row.split(None,2) iid = part[1] ## IID is the second column in phenofile index[iid] = row.rstrip() ## rstrip gets rid of \n and other white spaces shortfile.close() outfile = open( outfilename, "w") longfile= open( longfilename, "r" ) for row in longfile: part = row.split(None,6) iid = part[1] restofline = part[6] if iid in index: pheno = index[iid] outfile.write( pheno + ' ' + restofline) longfile.close() outfile.close() ## generate pheno.dat file infilename = ddir + temponame + '.map' outfilename = ddir + phenoname + '.dat' infile = open(infilename,'r') outfile = open(outfilename,'w') ## write covariates and phenotype names outfile.write('C igrowth\n') outfile.write('T logAUC\n') ## write one row per snp for linea in infile: part = linea.split(None,2) newlinea = 'M ' + part[1] + '\n' outfile.write(newlinea) infile.close() outfile.close()
Friday, April 13, 2012
create new theme for ggplot
from: http://sape.inf.usi.ch/quick-reference/ggplot2/themes theme_complete_bw <- function(base_size = 12) { structure(list( axis.line = theme_blank(), axis.text.x = theme_text(size = base_size * 0.8 , lineheight = 0.9, colour = "black", vjust = 1), axis.text.y = theme_text(size = base_size * 0.8, lineheight = 0.9, colour = "black", hjust = 1), axis.ticks = theme_segment(colour = "black"), axis.title.x = theme_text(size = base_size, vjust = 0.5), axis.title.y = theme_text(size = base_size, angle = 90, vjust = 0.5), axis.ticks.length = unit(0.15, "cm"), axis.ticks.margin = unit(0.1, "cm"), legend.background = theme_rect(colour=NA), legend.key = theme_rect(fill = NA, colour = "black", size = 0.25), legend.key.size = unit(1.2, "lines"), legend.text = theme_text(size = base_size * 0.8), legend.title = theme_text(size = base_size * 0.8, face = "bold", hjust = 0), legend.position = "right", panel.background = theme_rect(fill = NA, colour = "black", size = 0.25), panel.border = theme_blank(), panel.grid.major = theme_line(colour = "black", size = 0.05), panel.grid.minor = theme_line(colour = "black", size = 0.05), panel.margin = unit(0.25, "lines"), strip.background = theme_rect(fill = NA, colour = NA), strip.text.x = theme_text(colour = "black", size = base_size * 0.8), strip.text.y = theme_text(colour = "black", size = base_size * 0.8, angle = -90), plot.background = theme_rect(colour = NA, fill = "white"), plot.title = theme_text(size = base_size * 1.2), plot.margin = unit(c(1, 1, 0.5, 0.5), "lines") ), class = "options") }
Thursday, April 12, 2012
# cdf: cd's to frontmost window of Finder (by Yarko)
copy the following in ~/.bash_profile # cdf: cd's to frontmost window of Finder cdf () { currFolderPath=$( /usr/bin/osascript <<" EOT" tell application "Finder" try set currFolder to (folder of the front window as alias) on error set currFolder to (path to desktop folder as alias) end try POSIX path of currFolder end tell EOT ) # ignore the cd if it's my desktop if [ "$currFolderPath" != "$HOME/Desktop/" ] then echo "cd to \"$currFolderPath\"" cd "$currFolderPath" else echo "no finder path to cd to..." fi }
Friday, February 3, 2012
Thursday, February 2, 2012
python script extract variants from large file based on smaller file
#small script to extract variants from a large file based on a smaller file (by Vasa) largeChromosomes = {} largePositions = {} largeFile = open('ref1k.rs.snps.txt','r') for line in largeFile: line = line.split('\t') chrm = line [0] rs = line[1] pos = line[2] largeChromosomes[rs] = chrm largePositions[rs] = pos smallFile = open('reck.txt','r') fileOut = open('reck.1kpositions.txt','w') for line in smallFile: line = line.split('\t') rs = line[1] largeChrom = largeChromosomes[rs] largePos = largePositions[rs] lineOut = ' '.join( [rs, largeChrom, largePos] ) print >> fileOut, lineOut Below is a more stylish script that does the same: create a file named select.py, make it excutable and run > python select.py -s [name|number] selector_file -c [name|number] large_file -o output_file #!/usr/bin/env python ### # March 29th, 2011 # Yarko Tymciurak # yarkot@uchicago.edu # # Research Computing Group # Biostatistics Lab # University of Chicago #### ''' Given two files, select (output) lines of the second (data) file which contain one of the data items in the first (selector) file. ''' from __future__ import print_function from collections import namedtuple from optparse import OptionParser import sys if sys.version_info[0] < 3 and sys.version_info[0] == 2 and sys.version_info[1] < 6: print( 'This program needs a minimum of Python version 2.6 to run. You are using:\n%s' % sys.version, file=sys.stderr) exit(1) LINEEND = '\r\n' # for rstrip # FIELDSEP = None # for split error_log = sys.stderr def main(): useage = '''useage: %prog [-s [name|number] selector_file [-c [name|number] data_file [-o output_file]" Given two input files, the values of a specified column of a selector file will be used to select output. Data in the specified "compare" column of the data_file will be checked against the selector data. If a compare data item from the data_file exists in the selector set, then that data_file row (line) will be output. You may also specify an output file. - If a field name is given, the first line of the file is assumed to contain field names. - If a field number is given, the n-th field is used (left-to-right, beginning with 1); all lines are assumed to be data - Fields are assumed to be TAB separated. example: % %prog -s IID relationships.txt -c 2 some.ped -o filtered.ped This will use the "IID" column from relationships. Any row in "some.ped" which has column-2 data matching an IID data will be output to "filtered.ped" This is equivalent: % %prog -sIID relationships.txt -c2 some.ped -ofiltered.ped ''' parser = OptionParser(useage) parser.add_option( "-s", "--select-column", dest="select_column", help="column from which to build selection matching data") parser.add_option( "-c", "--compare-column", dest="compare_column", help="column to compare against selection criteria") parser.add_option( "-o", "--output", dest="output", help="output file for selected data") parser.add_option( "-p", "--separator", dest="FIELDSEP", help="set field separator (each string will be one separator).\n\ default separator: any successive whitespace") (options,args) = parser.parse_args() output = options.output select_column = proper_type(options.select_column) compare_column = proper_type(options.compare_column) compare_asindex = type(compare_column) is int global FIELDSEP FIELDSEP = options.FIELDSEP # I depend on this being 'None' when not set if (select_column is None) or (compare_column is None): error_log.write("Need to specify select column (-s) and compare column (-c).\nTry -h option for help.\n") exit(1) if len(args)<2: parser.print_help() exit(1) fname = args[0] fp = sys.stdin if fname == '-' else must_open(fname) fo = sys.stdout if output is None else must_open(output, 'w') selectors = get_selectors(fp, select_column) if type(select_column) is int: select_column -= 1 # adjust for zero-based array indexing for fname in args[1:]: global n n = 0 fp = sys.stdin if fname == '-' else must_open(fname) line = fp.readline() # assume first line is a header line, if named data field: if not compare_asindex: dat = namedtuple("dat", line.rstrip(LINEEND).split(FIELDSEP)) line = fp.readline() else: maxsplit = compare_column compare_column -= 1 # i.e. 2nd column => row[1] while not (line == ''): n+=1 # split the line fields if compare_asindex: line_element = line.rstrip(LINEEND).split(FIELDSEP, maxsplit) else: drow = dat(*line.rstrip(LINEEND).split(FIELDSEP)) line_element = drow._asdict() # output if the specified data field is in the selector try: if line_element[compare_column] in selectors: fo.write(line) except Exception as e: print( e, "\nMaybe you need to specify an alternate field separator to process your data?", file=sys.stdout); return line = fp.readline() def get_selectors(fp, column): ''' using the global option, select a column from the file, and return a dict (hash performance) with all the values ''' selectors = {} global FIELDSEP # Get column option: # - if numeric, split the fields and use number as an index, # - else use named.tuples, and use the first line as the header asindex = type(column) is int if not asindex: # get the first line, which we expect to be the column header line = fp.readline() hdr = namedtuple("hdr", line.rstrip(LINEEND).split(FIELDSEP)) else: # can only limit splits on numerics maxsplit = column column -= 1 # i.e. 2nd column => row[1] # now go thru the file: line = fp.readline() while not (line==''): # prepare so we index correctly either way: if asindex: row = line.rstrip(LINEEND).split(FIELDSEP, maxsplit) else: drow = hdr(*line.rstrip(LINEEND).split(FIELDSEP)) row = drow._asdict() selectors[row[column]]='' # we only care about key, not value line = fp.readline() return selectors def must_open(f, c='r'): try: fp = open(f,c) except IOError as e: error_log.write('Unable to open %s : %s\n' % (f,e)) exit(2) return fp def proper_type(i): return int(i) if (i and i.isdigit()) else i if __name__=='__main__': main() ##----------
Wednesday, January 11, 2012
Friday, January 6, 2012
latexdiff - mark up differences between latex files
Determine and mark up significant differences between latex files. http://www.ctan.org/tex-archive/support/latexdiff This perl script will generate a latex file with changes marked up (similar to Word) from two latex files latexdiff-so fileold.tex filenew.tex > dif.tex
ps2pdf to all ps files in current directory
for x in $(ls *.ps); do echo $x; ps2pdf $x $(echo $x|sed -e 's/ps$/pdf/');done or more efficiently according to Yarko's comment for x in *.ps; do echo $x; ps2pdf $x ${x/%ps/pdf}; done
Thursday, June 3, 2010
Friday, March 19, 2010
awk: verify same number of columns
## prints number of columns if it changed from previous line > awk -F"\t" 'NF != oldnf { print NF; oldnf = NF }' filename |head |head added just in case file is very long ## using a script > awk -f script.awk filename | head script.awk: BEGIN { FS="\t" oldnf = 1 } { if(NF != oldnf) { print NF oldnf = NF } } Other examples in http://sparky.rice.edu/~hartigan/awk.html
Friday, March 5, 2010
Tuesday, February 16, 2010
running R64 in aquamacs
http://www.matthewckeller.com/html/aquamacs.html USING 64-BIT R FROM WITHIN AQUAMACS 1) Aquamacs is terrific because it comes bundled with about everything you need to start using R with it. No need to separately download ESS (emacs speaks statistics) or mess with the .ess-lisp files. Download Aquamacs from http://aquamacs.org/ and install it. 2) Now any file with an “.R” extension that is opened with aquamacs will automatically have syntax highlighting AND will allow you to start 64-bit R. I highly recommend checking out this page, http://ess.r-project.org/, and downloading the ESS reference card therein if you are new. Emacs has a bit of a learning curve, but you’ll begin loving its capabilities as an aid to programming very soon. 3) To start 64-bit R from within aquamacs hit Control-u then Alt-x then “R” then. Aquamacs will ask you for “Starting Args”. Here’s where you tell it you want to run 64-bit R. Type “--arch=x86_64” then . A new window will open up that is the R session. 4) That’s almost it. Just one more issue: graphing will crash (something to do with the new R and X11). Aquamacs has X11 as the default (null) graphics device. To change this, type in R: “options(device=”quartz”)”. Now your null graphics device is quartz and it should all work out. If you really want to use X11 to write graphics, you can use x11(type="Xlib")' for each new graph. What I do is to set “options(device=”quartz”) within my Rprofile.site file.
Monday, February 15, 2010
Tuesday, December 15, 2009
pvalue plot vs uniform; FDR
qqunif = function(p,BH=T,...) { nn = length(p) xx = -log10((1:nn)/(nn+1)) plot( xx, -sort(log10(p)), xlab=expression(Expected~~-log[10](italic(p))), ylab=expression(Observed~~-log[10](italic(p))), ... ) abline(0,1,col='gray') if(BH) { lines( xx, -log10(0.05*(1:nn)/(nn+1)), col='red') lines( xx, -log10(0.10*(1:nn)/(nn+1)), col='orange') lines( xx, -log10(0.25*(1:nn)/(nn+1)), col='yellow') legend('bottomright', c("FDR = 0.05","FDR = 0.10","FDR = 0.25"), col=c('red','orange','yellow'),lty=1, cex=1.4) } }
Tuesday, December 8, 2009
imagesc in CDAT
The imagesc function in MATLAB creates plots that have color bars scaled to a user-specified range. This allows you to simply create a whole series of plots that can be easily intercompared. The following function imitates imagesc: import vcs def imagesc(x, mini, maxi): t = vcs.init() a = t.getboxfill('quick') a.level_1 = mini a.level_2 = maxi t.plot(x, a) x is the input array and mini and maxi define the range in values to plot. The function establishes a VCS canvas, imports the "quick" boxfill graphics method, sets the level range to mini and maxi, and plots x using this customized graphics method. other tips for CDAT/Python check http://www.johnny-lin.com/cdat_tips/
Thursday, December 3, 2009
likelihood ratio test
> logLik.test function(fit0,fit) { l0 = logLik(fit0) l1 = logLik(fit) lratio = abs(as.numeric(l0)-as.numeric(l1)) df = abs( attr(l1,'df') - attr(l0,'df') ) pval = 1-pchisq( 2*lratio, df) return(pval) }
log likelihood from lm, glm, polr
> fit = lm(y ~ x) > logLik(fit) 'log Lik.' -36.4 (df=4) > attr(logLik(fit),'df') [1] 4
Wednesday, November 25, 2009
Tuesday, November 17, 2009
Monday, October 26, 2009
plots boxplot, stripchart and mean
## CAN BE REPLACED BY qplot in ggplot2 package
qplot(x,y,geom=c("boxplot","jitter")) ## plots boxplot, stripchart and mean boxjitter = function(x,y=NULL,border='gray',jitter=.1,vertical=T,...) { if(!is.null(y)) { boxplot(y~x,border=border,ylim = range(y,na.rm=T),outline=F,...) stripchart(y~x,vertical=vertical,method="jitter",jitter=jitter,add=T) meanvec = tapply(y,x,mean.na) points(1:length(meanvec),meanvec,pch="M",col='blue') } else { x = x[!is.na(x)] boxplot(x,border=border,ylim = range(x),outline=F,...) stripchart(x,vertical=vertical,method="jitter",jitter=jitter,add=T) points(1,mean.na(x),pch="M",col='blue') } }
Thursday, October 22, 2009
calculate number of minor alleles from A G format
num.minal = function(a1,a2) { aall = c(a1,a2) tab = table(aall) miname = names(tab)[tab==min(tab)] apply(cbind(a1==miname,a2==miname),1,sum) }
plink coding --recodeAD
plink --file data --recodeAD which, assuming C is the minor allele, will recode genotypes as follows: SNP SNP_A , SNP_HET --- ----- ----- A A -> 0 , 0 A C -> 1 , 1 C C -> 2 , 0 0 0 -> NA , NA
R table, percentages and chi square test like in stata
table.all = function(...) { args = list(...) dnn = names(args) x = args[[1]] y = args[[2]] print(table(x,y,dnn=dnn)) print("percentage by row") print( round( prop.table(table(x,y,dnn=dnn),1) * 100 ) ) print("percentage by col") print( round( prop.table(table(x,y,dnn=dnn),2) * 100 ) ) print(chisq.test(table(x,y,dnn=dnn)) ) }
Friday, October 2, 2009
order data frames in R
say data has read and prog as colums data[order(read, prog), ] this will order first by read then by prog data[order(-read), ] - reverses the order ** there can be conflicts if read is a variable outside of the data frame. Use data[order(data[,1]),] assuming read is column 1 from: http://www.ats.ucla.edu/stat/R/faq/sort.htm
Thursday, October 1, 2009
list names from data that contain charname
## list names from data frames that contain charname grepnames = function(charname,data) { names(data)[grep(charname,names(data))] }
Friday, September 25, 2009
power calculation in SAS
proc power; twosamplefreq test=pchi groupproportions = (.5034 .6459) power = . groupns = ( 1494 373) alpha = 0.00005; run; proc power; twosamplesurvival test=logrank gexphs = 0.6733 | 0.4155 accrualtime = .00001 follouptime = 1 groupns = 200 | 200 grouplossexphazards = (0 0) power = .; proc power; twosamplesurvival test=logrank curve("Control") = (1):(.45) curve("Treatment") = (1):(.66) groupsurvival = "Control" | "Treatment" GROUPLOSSEXPHAZARDS = (.2231 .2231) /*grouplossexphazards = (0,0)*/ accrualtime = .00001 follouptime = 1 groupns = 120 | 120 power = .; run; proc power; twosamplesurvival test=logrank curve("Control") = (1):(.51) curve("Treatment") = (1):(.66) groupsurvival = "Control" | "Treatment" GROUPLOSSEXPHAZARDS = (.2231 .2231) /*grouplossexphazards = (0,0)*/ accrualtime = .00001 follouptime = 1 groupns = 100 | 100 power = .; run; proc power; twosamplesurvival test=logrank curve("Control") = (1):(.45) curve("Treatment") = (1):(.70) groupsurvival = "Control" | "Treatment" GROUPLOSSEXPHAZARDS = (.2231 .2231) /*grouplossexphazards = (0,0)*/ accrualtime = .00001 follouptime = 1 groupns = 200 | 200 power = .; run;
how to get rid of emac's automatic switching of _ into ->
Solution by Paul R. (thanks!) M-x set-variableess-S-assign "-" That's it.
Monday, April 13, 2009
File Management in Python
( Page 1 of 5 )
File management is a basic function, and an important part of many applications. Python makes file management surprisingly easy, especially when compared to other languages. Peyton McCullough explains the basics.
Introduction
The game you played yesterday uses files to store game saves. The order you placed yesterday was saved in a file. That report you typed up this morning was, obviously, stored in a file as well.
File management is an important part of many applications written in nearly every language. Python is no exception to this. In this article, we will explore the task of manipulating files using several modules. We'll read, write to, append and do other strange things to files. Let's get started.
Reading and Writing
The most basic tasks involved in file manipulation are reading data from files and writing data to files. This is a very simple task to learn. Let's open a file for writing:
fileHandle = open ( 'test.txt', 'w' )
The "w" indicates that we will be writing to the file, and the rest is pretty simple to understand. The next step is to write data to the file:
fileHandle.write ( 'This is a test.\nReally, it is.' )
This will write the string "This is a test." to the file's first line and "Really, it is." to the file's second line. Finally, we need to clean up after ourselves and close the file:
fileHandle.close()
As you can see, it's very easy, especially with Python's object orientation. Note that when you use the "w" mode to write to the file again, all its contents will be deleted. To get past this, use the "a" mode to append data to a file, adding data to the bottom:
fileHandle = open ( 'test.txt', 'a' )
fileHandle.write ( '\n\n\nBottom line.' )
fileHandle.close()
Now let's read our file and display the contents:
fileHandle = open ( 'test.txt' )
print fileHandle.read()
fileHandle.close()
This will read the entire file and print the data within it. We can also read a single line in the file:
fileHandle = open ( 'test.txt' )
print fileHandle.readline() # "This is a test."
fileHandle.close()
It is also possible to store the lines of a file into a list:
fileHandle = open ( 'test.txt' )
fileList = fileHandle.readlines()
for fileLine in fileList:
print '>>', fileLine
fileHandle.close()
When reading a file, Python's place in the file will be remembered, illustrated in this example:
fileHandle = open ( 'test.txt' )
garbage = fileHandle.readline()
fileHandle.readline() # "Really, it is."
fileHandle.close()
Only the second line is displayed. We can, however, get past this by telling Python to resume reading from a different position:
fileHandle = open ( 'test.txt' )
garbage = fileHandle.readline()
fileHandle.seek ( 0 )
print fileHandle.readline() # "This is a test."
fileHandle.close()
In the above example, we tell Python to continue reading from the first byte in the file. Thus, the first line is printed. We can also request Python's place within the file:
fileHandle = open ( 'test.txt' )
print fileHandle.readline() # "This is a test."
print fileHandle.tell() # "17"
print fileHandle.readline() # "Really, it is."
It is also possible to read the file a few bytes at a time:
fileHandle = open ( 'test.txt' )
print fileHandle.read ( 1 ) # "T"
fileHandle.seek ( 4 )
print FileHandle.read ( 1 ) # "T"
When working with Windows and Macintosh, sometimes you are required to read and write files in binary mode, such as images or executional files. To do this, simply append "b" to the file mode:
fileHandle = open ( 'testBinary.txt', 'wb' )
fileHandle.write ( 'There is no spoon.' )
fileHandle.close()
fileHandle = open ( 'testBinary.txt', 'rb' )
print fileHandle.read()
fileHandle.close()
#write to file
f = open('c:/temp/workfile','w')
f.write('hallo')
f.close
#open from file
f = open('file.txt')
#read linewise
for i in f:
print i
#read characterwise
for i in f.read():
print i
Friday, July 13, 2007
myfunctions.r
## logit/expit
logit = function(x,b=1) log(x/(b-x))
expit = function(x,b=1) b/(1+exp(-x))
## matlab equivalent of repmat in R
repmat = function(X,m,n){
## tiles matrix X, m by n times
mx = dim(X)[1]
nx = dim(X)[2]
matrix(t(matrix(X,mx,nx*n)),mx*m,nx*n,byrow=T)
}
acfi = function(x, lag.max = NULL,
type = c("correlation", "covariance", "partial"),
plot = TRUE, demean = TRUE,...)
{
acf(x, lag.max = lag.max,
type = type,
plot = plot, na.action = na.pass, demean = TRUE, ...)
}
"%&%" <- function(a, b) paste(a, b, sep="")
rangi = function(x){
range(x, na.rm = T)
}
cori = function(x,y=NULL){
cor(x, y = y, use = "complete.obs")
}
## myoptim
## minimizes fun using optim with nelder mead
## algorithm.
myoptim = function(param,fun,epsi=1e-5,hess=F){
dife = 10
eini = fun(param)
while(dife>epsi){
res=optim(param,fun,hessian=hess)
dife = abs(eini-res$value)
param=res$par
eini=res$value
}
res
}
##======================
## mean squared error sum((x-y)^2)/n
mse <- function(x,y) {
n <- length(x)
sum((x-y)^2)/n}
rmse <- function(x,y) sqrt(mse(x,y))
##======================
regress <- function(form,plot=F){
fit=lm(form)
fitsum=summary(fit);
print(fitsum$coeff);
print(c("R squared","residual se"))
print(round(c(fitsum$r.squared,rmse(fit$res,0)),3))
}
## Great circle distance from library fields, default is km.
gcdist <- function (loc1, loc2, miles = FALSE, R = NULL)
{
if (is.null(R)) {
if (miles)
R <- 3963.34
else R <- 6378.388
}
if (missing(loc2))
loc2 <- loc1
coslat1 <- cos((loc1[, 2] * pi)/180)
sinlat1 <- sin((loc1[, 2] * pi)/180)
coslon1 <- cos((loc1[, 1] * pi)/180)
sinlon1 <- sin((loc1[, 1] * pi)/180)
coslat2 <- cos((loc2[, 2] * pi)/180)
sinlat2 <- sin((loc2[, 2] * pi)/180)
coslon2 <- cos((loc2[, 1] * pi)/180)
sinlon2 <- sin((loc2[, 1] * pi)/180)
pp <- cbind(coslat1 * coslon1, coslat1 * sinlon1, sinlat1) %*%
t(cbind(coslat2 * coslon2, coslat2 * sinlon2, sinlat2))
R * acos(ifelse(pp > 1, 1, pp))
}
## cord distance, default is km.
## loc1 = [lon, lat ]
cordist <- function (loc1, loc2, miles = FALSE, R = NULL)
{
if (is.null(R)) {
if (miles)
R <- 3963.34
else R <- 6378.388
}
if (missing(loc2))
loc2 <- loc1
coslat1 <- cos((loc1[, 2] * pi)/180)
sinlat1 <- sin((loc1[, 2] * pi)/180)
coslon1 <- cos((loc1[, 1] * pi)/180)
sinlon1 <- sin((loc1[, 1] * pi)/180)
coslat2 <- cos((loc2[, 2] * pi)/180)
sinlat2 <- sin((loc2[, 2] * pi)/180)
coslon2 <- cos((loc2[, 1] * pi)/180)
sinlon2 <- sin((loc2[, 1] * pi)/180)
pp <- cbind(coslat1 * coslon1, coslat1 * sinlon1, sinlat1) %*%
t(cbind(coslat2 * coslon2, coslat2 * sinlon2, sinlat2))
R * sqrt( 2* (1-ifelse(pp > 1, 1, pp) ) )
}
## matern function with Handcock's parameterization
## hmatern
hmatern = function(u,range,smoo){
if (is.vector(u)){
names(u) <- NULL
y = u
y[]=1
}
if (is.matrix(u)) {
dimnames(u) <- list(NULL, NULL)
y = u
y[,]=1
}
unonzero= u>0
if(smoo<100) {
urange = u*2*sqrt(smoo)/range
y[unonzero] = (urange[unonzero]^smoo) * besselK(urange[unonzero],smoo)/
(2^(smoo - 1))/ gamma(smoo)}
else
{y[unonzero] = exp(-u[unonzero]^2)}
y
}
##===========================================================
## simple useful functions
##===========================================================
suma <- function(x) {
indnna = !is.na(x)
if(sum(indnna)>0) res = sum(x[indnna]) else res=NA
res
}
maxi <- function(x){
indnna = !is.na(x)
if(sum(indnna)>0) res=max(x[indnna]) else res=NA
res}
mini <- function(x){
indnna = !is.na(x)
if(sum(indnna)>0) res=min(x[indnna]) else res=NA
res}
meana <- function(x){
indnna = !is.na(x)
if(sum(indnna)>0) res=mean(x[indnna]) else res=NA
res}
vari <- function(x){
indnna = !is.na(x)
if(sum(indnna)>0) res=var(x[indnna]) else res=NA
res
}
longi <- function(data){length(data[,1])}
plotfit <- function(fit)
{
par( mfrow=c(2,2) )
plot(fit)
par( mfrow=c(1,1) )
}
algunos <- function(x,cant=10) x[1:cant,]
## returns the row and column of an index matrix == 1
indmat <- function(x)
{
n <- length(x[,1])
tm1 <- seq(1,n)
tm2 <- matrix(rep(1,n*n),n)
rowmat <- diag(tm1)%*%tm2
colmat <- tm2%*%diag(tm1)
ro <- rowmat[x==1]
co <- colmat[x==1]
cbind(ro,co)
}
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