![](/img/trans.png)
[英]How to create a new column with Pandas after x number of rows from a CSV file?
[英]How to create a csv file from a txt file with column separator after “x” amount of characters
我有一個看起來像這樣的 txt 文件:
MT0111500000000 Anniston-Oxford-Jacksonville, AL Metropolitan Statistical Area
MT0112220000000 Auburn-Opelika, AL Metropolitan Statistical Area
MT0113820000000 Birmingham-Hoover, AL Metropolitan Statistical Area
我需要從中創建一個 csv 文件,我對此幾乎沒有經驗,但一直在學習和做,雖然可能效率不高。
我現在的問題是,當我使用 pandas 時,它會在“,”之后創建列。 我需要的是列分隔符位於左側代碼“MT0113820000000”之后,盡管代碼確實發生了變化,但它們的長度都相同。
在此先感謝,我知道這是一個非常noobie的問題。
這是我目前的代碼:
import pandas as pd
dataframe1 = pd.read_csv("C:/Users/andre/Desktop/bea_api_test/python-bureau-economic-analysis-api-client/testttt/output.txt")
dataframe1.to_csv('output_.csv', index = None)
和 output:
COLUMN 1 COLUMN 2
MT0111500000000 Anniston-Oxford-Jacksonville | AL Metropolitan Statistical Area
或者,使用上面評論中提到的read_fwf
:
from io import StringIO
import pandas as pd
testdata = '''\
MT0111500000000 Anniston-Oxford-Jacksonville, AL Metropolitan Statistical Area
MT0112220000000 Auburn-Opelika, AL Metropolitan Statistical Area
MT0113820000000 Birmingham-Hoover, AL Metropolitan Statistical Area
'''
buff = StringIO(testdata)
df = pd.read_fwf(buff, header=None, colspecs=[(0, 15), (16, 64 * 1024)])
print(df.to_csv(index=False, columns=[0, 1], header=['COLUMN1', 'COLUMN2']))
這不是 CSV 並且我看不到說服read_csv
做正確事情的便捷方法。 幸運的是,這里似乎有一個簡單的規則。 第一個空格之前的東西,然后是之后的東西。 str.split
這樣做的。
import pandas as pd
from pathlib import Path
#in_file = Path("C:/Users/andre/Desktop/bea_api_test/python-bureau-economic-analysis-api-client/testttt/output.txt")
in_file = Path("test.txt")
out_file = in_file.with_name(in_file.stem + "_").with_suffix(".csv")
# test data
open(in_file, "w").write("""\
MT0111500000000 Anniston-Oxford-Jacksonville, AL Metropolitan Statistical Area
MT0112220000000 Auburn-Opelika, AL Metropolitan Statistical Area
MT0113820000000 Birmingham-Hoover, AL Metropolitan Statistical Area""")
# convert to csv
pd.DataFrame([line.strip().split(" ",1) for line in open(in_file)],
columns=["COLUMN1", "COLUMN2"]).to_csv(out_file, index=None, headr=False)
# visual verification
print(open(out_file).read())
Output
MT0111500000000,"Anniston-Oxford-Jacksonville, AL Metropolitan Statistical Area"
MT0112220000000,"Auburn-Opelika, AL Metropolitan Statistical Area"
MT0113820000000,"Birmingham-Hoover, AL Metropolitan Statistical Area"
在此示例中,我立即編寫了 csv,以便自動從 memory 中刪除 dataframe。 您也可以使用 CSV 模塊執行此操作,一次寫入一行。 這將使用更少的 memory,因為它不必將整個文件保存在 memory 中。 由於csv
是標准 python 庫的一部分,因此對pandas
沒有外部依賴。 添加一些文件名處理
import csv
from pathlib import Path
#in_file = Path("C:/Users/andre/Desktop/bea_api_test/python-bureau-economic-analysis-api-client/testttt/output.txt")
in_file = Path("test.txt")
out_file = in_file.with_name(in_file.stem + "_").with_suffix(".csv")
# test data
open(in_file, "w").write("""\
MT0111500000000 Anniston-Oxford-Jacksonville, AL Metropolitan Statistical Area
MT0112220000000 Auburn-Opelika, AL Metropolitan Statistical Area
MT0113820000000 Birmingham-Hoover, AL Metropolitan Statistical Area""")
# convert to csv
with open(in_file) as infp, open(out_file, "w") as outfp:
writer = csv.writer(outfp)
writer.writerows(line.strip().split(" ",1) for line in infp)
# visual verification
print(open(out_file).read())
您可以在第一次出現空格時拆分數據:
data = pd.read_table("data.txt", squeeze = True, header = None).str.split(" ", 1)
df = pd.DataFrame(data.tolist(), columns = ["column1", "column2"])
df.to_csv("df.csv")
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.