python - pandas read_csv usecols and names out of sync -


when trying read columns using indices tabular file pandas read_csv seems usecols , names out of sync each other.

for example, having file test.csv:

foo   -46450.494736   0.0728830817231 foo   -46339.7126846  0.0695018062805 foo   -46322.4942905  0.0866205763556 foo b   -46473.3117983  0.0481618121947 foo b   -46537.6827055  0.0436893868921 foo b   -46467.2102205  0.0485001911304 bar c   -33424.1224914  6.7981041851 bar c   -33461.4101485  7.40607068177 bar c   -33404.6396495  4.72117502707

and trying read 3 columns index without preserving original order:

cols = [1, 2, 0] names = ['x', 'y', 'z']  df = pd.read_csv(                 'test.csv', sep='\t',                 header=none,                 index_col=none,                 usecols=cols, names=names)

i'm getting following dataframe:

     x  y             z 0  foo  -46450.494736 1  foo  -46339.712685 2  foo  -46322.494290 3  foo  b -46473.311798 4  foo  b -46537.682706 5  foo  b -46467.210220 6  bar  c -33424.122491 7  bar  c -33461.410148 8  bar  c -33404.639650

whereas expect column z have foo , bar, this:

     z  x             y 0  foo  -46450.494736 1  foo  -46339.712685 2  foo  -46322.494290 3  foo  b -46473.311798 4  foo  b -46537.682706 5  foo  b -46467.210220 6  bar  c -33424.122491 7  bar  c -33461.410148 8  bar  c -33404.639650

i know pandas stores dataframes dictionary order of columns may different requested usecols, problem here using usecols indices , names doesn't make sense.

i need read columns indices , assign names them. there workaround this?

the documentation clearer on (feel free make issue, or better submit pull request!) usecols set-like - not define order of columns, tested against membership.

from io import stringio  pd.read_csv(stringio("""a,b,c 1,2,3 4,5,6"""), usecols=[0, 1, 2])  out[31]:      b  c 0  1  2  3 1  4  5  6  pd.read_csv(stringio("""a,b,c 1,2,3 4,5,6"""), usecols=[2, 1, 0])  out[32]:      b  c 0  1  2  3 1  4  5  6

names on other hand ordered. in case, answer specify names in order want them.


Comments

Post a Comment

Popular posts from this blog

node.js - Node js - Trying to send POST request, but it is not loading javascript content -

i have been trying send post request website, , has not been loading full site. i guessing problem node js not loading javascript content, executing it. can see javascript in response, though never loads content javascript files producing in html. what mean is, doesn't execute javascript. how make node js code overcome this, , wait the full website load? have tried native code, , "request' module, both producing same errors. if helps, don't need native javascript. modules fine. some code have tried (request module): var options = { method: 'post', uri: 'https://url', formdata: { 'email': 'email', 'prize': '0', 'transactional': 'on' }, headers: { /* 'content-type': 'application/x-www-form-urlencoded' */ // set automatically } }; rp(options) .then(function (body) { console.log(body) }) .catch(function (err) { console.log(err) }); when fetch content...
Read more

javascript - Replicate keyboard event with html button -

i have tried few ways make happen. have javascript pinball game uses keyboard keys controls. converting application touch screen display. workaround, hoping overlay buttons when clicked simulate keyboard strokes. have done research , sounds should work. using jquery v3.2.1 here things have tried far... html element: <input type="button" class="coil"></input> $('.coil').trigger({type: 'keydown', which: 40, keycode: 40}); with this, not errors, nothing happens. var coilkey = $('body').keydown(function(e) { switch (e.keycode) { case 40: break;} }) $('.coil').click(coilkey); this 1 returns error in console... ((jquery.event.special[handleobj.origtype] || (intermediate value)).handle || handleobj.handler).apply not function below javascript game engine handles key listeners... addkeylistener: function (keyandlistener) { this.keylisteners.push(keyandlistener); }, // gi...
Read more

javascript - Web audio api 5.1 surround example not working in firefox -

i've been playing lott lately web audio api on both firefox , chrome. few days ago started experiment surround set. when trying surround audio in web audio api came notice example works fine in chrome v59 not in firefox v54. // create web audio api context var audioctx = new (window.audiocontext || window.webkitaudiocontext)(); audioctx.destination.channelinterpretation = 'discrete'; audioctx.destination.channelcountmode = 'explicit'; audioctx.destination.channelcount = 6; var oscillators = []; var merger = audioctx.createchannelmerger(6); console.log(audioctx.destination, merger); //merger.channelinterpretation = 'discrete'; //merger.channelcountmode = 'explicit'; //merger.channelcount = 6; var addoscilator = function(channel, frequency) { var oscillator = audioctx.createoscillator(); oscillator.frequency.value = frequency; // value in hertz oscillator.connect(merger,0,channel); oscillator.start(); oscillators.push(o...
Read more