删除txt文件中的换行符

Question

I'm doing Euler Problems and am at problem #8 and wanted to just copy this huge 1000-digit number to a numberToProblem8.txt file and then just read it into my script but I can't find a good way to remove newlines from it. With that code:

hugeNumberAsStr = ''

with open('numberToProblem8.txt') as f:
    for line in f:
        aSingleLine = line.strip()
        hugeNumberAsStr.join(aSingleLine)

print(hugeNumberAsStr)

Im using print() to only check if it works and well, it doesnt. It doesnt print out anything. What's wrong with my code? I remove all the trash with strip() and then use join() to add that cleaned line into hugeNumberAsStr (need a string to join those lines, gonna use int() later on) and its repeated for all the lines. Here is the .txt file with a number in it.

Answer 1

You need to do hugeNumberAsStr += aSingleLine instead of hugeNumberAsStr.join(..)

str.join() joins the passed iterator and return the string value joined by str . It doesn't update the value of hugeNumberAsStr as you think. You want to create a new string with removed \\n . You need to store these values in new string. For that you need append the content to the string

Answer 2

What about something like:

hugeNumberAsStr = open('numberToProblem8.txt').read()
hugeNumberAsStr = hugeNumberAsStr.strip().replace('\n', '')

Or even:

hugeNumberAsStr = ''.join([d for d in hugeNumberAsStr if d.isdigit()])

I was able to simplify it to the following to get the number from that file:

>>> int(open('numberToProblem8.txt').read().replace('\n',''))
731671765313306249192251196744265747423553491949349698352031277450632623957831801698480186947885184385861560789112949495459501737958331952853208805511125406987471585238630507156932909632952274430435576689664895044524452316173185640309871112172238311362229893423380308135336276614282806444486645238749303589072962904915604407723907138105158593079608667017242712188399879790879227492190169972088809377665727333001053367881220235421809751254540594752243525849077116705560136048395864467063244157221553975369781797784617406495514929086256932197846862248283972241375657056057490261407972968652414535100474821663704844031998900088952434506585412275886668811642717147992444292823086346567481391912316282458617866458359124566529476545682848912883142607690042242190226710556263211111093705442175069416589604080719840385096245544

Answer 3

The join method for strings simply takes an iterable object and concatenates each part together. It then returns the resulting concatenated string. As stated in help(str.join):

join(...) S.join(iterable) -> str

Return a string which is the concatenation of the strings in the
iterable.  The separator between elements is S.

Thus the join method really does not do what you want. The concatenation line should be more like:

hugeNumberAsString += aSingleLine

Or even:

hugeNumberAsString += line.strip()

Which gets rid of the extra line of code doing the strip.