python - How to replace values in a column in a fast and memory efficient manner -


i have dataframe containing 114 million records 2 columns named session_id , artifact_id. both columns categorical. replace values in column artifact_id values in dictionary each value in artifact_id mapped value. artifact_id int column , values replaced int values. there 322k unique values replaced.

here's sample dataset:

session_id    artifact_id                  234                  123     b              123     b              678

the contents of dictionary follows:

{'234':'1','123':'2','678':'3'}

i final dataset this:

session_id    artifact_id                  1                  2     b              2     b              3

i have thought following statement replace these values:

sessions['artifact_id'].replace(artifactid2num, inplace=true)

artifactid2num name of dictionary. statement gives me out of memory error. thought breaking process various pieces avoid memoryerror using following code:

count = 0 idx in xrange(0,len(sessions),50000):     count = count + 1     print(count)     if (idx+50000) > len(sessions):         sessions[idx:(len(sessions)-1)]['artifact_id'].replace(artifactid2num, inplace=true)     else:         sessions[idx:(idx+50000)]['artifact_id'].replace(artifactid2num, inplace=true)

the above code runs far without errors. has been running 10+ hours , hasn't finished yet.

more info: original dataframe 114 million records fits in memory , takes 4.2 gb. moment run above code iterations, memory occupancy increases 20gb. i'm working on 50000 records @ time , replacing values dictionary. why memory usage increase drastically?

is there way make code faster? or there way can achieve same result?

any appreciated.

can try:

d = {'123': '2', '234': '1', '678': '3'} df['artifact_id'] = df.artifact_id.astype(str).map(d)

Comments

Post a Comment

Popular posts from this blog

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m
Read more

javascript - Z-index in d3.js -

i have map , when hover effect on region of map below yellow line , circle, last ones disappear. how can solve problem? http://jsfiddle.net/ot21n9qx/ var arc = g.append("path") .style("fill", "none") .style("stroke", "yellow") .style("stroke-width", 2) .attr("d", "m" + pathorigin[0] + "," + pathorigin[1] + " q" + svgpoint[0] + "," + pathorigin[1] + " " + svgpoint[0] + "," + svgpoint[1]); var circlesize = d3.scale.linear() .domain([0, 0.5, 1]) .range([4, 10, 4]); svg not have z order draws objects in order created. need create path , circle after create highlight regions. here forked fiddle: http://jsfiddle.net/o00fzgaf/1/
Read more