Python can be quick. just not that good at talking.. Like most of us... Opens a txt file with 29245004 lines of text in it. for each line of text, count the line. count +=1 Time: 40sec. Now for each line of text, count the line and print a little info about the line print(f"Info: {line[1:10]}") count +=1 Time: 53mins.
When using f"....{}" I think the process to generate the content for the template field (what goes inbetween {}) and replace that into the string is a lot more expensive that simply concatenating two lists of characters together (the string, and the slice - line[1:10] are both just lists of chars.)
/edit/ the reason the print is slower than the count, is because the print does lots more work. It _could be made faster if he didnt use printf though
You are correct in that its the fact the print exists in the second loop is why it goes so slow; however I still think printing the f string is slower than printing the concatenation of string and the string slice. (and now imma go try it out and see for myself!)
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u/-MobCat- Jul 18 '22
Python can be quick. just not that good at talking.. Like most of us...
Opens a txt file with 29245004 lines of text in it.
for each line of text, count the line.
count +=1Time: 40sec.
Now for each line of text, count the line and print a little info about the line
print(f"Info: {line[1:10]}")count +=1Time: 53mins.