pandas 保存熊猫数据框但保留 NA 值
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Save pandas dataframe but conserving NA values
提问by Náthali
I have this code
我有这个代码
import pandas as pd
import numpy as np
import csv
df = pd.DataFrame({'animal': 'cat dog cat fish dog cat cat'.split(),
'size': list('SSMMMLL'),
'weight': [8, 10, 11, 1, 20, 12, 12],
'adult' : [False] * 5 + [True] * 2});
And I changed the weight with NA values:
我用 NA 值改变了权重：
df['weight'] = np.nan
And finally I saved it
最后我保存了它
df.to_csv("ejemplo.csv", sep=";", decimal=",", quoting=csv.QUOTE_NONNUMERIC, index=False)
But when I read the file I have "", instead of NA I want to put NA instead of Nan
但是当我阅读文件时我有“”，而不是 NA 我想把 NA 而不是 Nan
I want as output:
我想作为输出：
adult;animal;size;weight
False;"dog";"S";NA
False;"cat";"M";NA
采纳答案by crashMOGWAI
To get that specific output, you'll have to pass the quotes in explicitly.
要获得该特定输出，您必须明确传递引号。
df = pd.DataFrame({'animal': r'"cat" "dog" "cat" "fish" "dog" "cat" "cat"'.split(),
'size': list(r'"S" "S" "M" "M" "M" "L" "L"'.split()),
'weight': [8, 10, 11, 1, 20, 12, 12],
'adult' : [False] * 5 + [True] * 2});
df['weight'] = '%s' %('NA')
df.to_csv("ejemplo.csv", sep=';', decimal=',',quoting=csv.QUOTE_NONE, index=False)
回答by EdChum
If you want a string to represent NaNvalues then pass na_repto to_csv:
如果你想要一个字符串来表示NaN值，那么传递na_rep给to_csv：
In [8]:
df.to_csv(na_rep='NA')
Out[8]:
',adult,animal,size,weight\n0,False,cat,S,NA\n1,False,dog,S,NA\n2,False,cat,M,NA\n3,False,fish,M,NA\n4,False,dog,M,NA\n5,True,cat,L,NA\n6,True,cat,L,NA\n'
If you want the NAin quotes then escape the quotes:
如果你想要NA引号，然后转义引号：
In [3]:
df = pd.DataFrame({'animal': 'cat dog cat fish dog cat cat'.split(),
'size': list('SSMMMLL'),
'weight': [8, 10, 11, 1, 20, 12, 12],
'adult' : [False] * 5 + [True] * 2})
df['weight'] = np.NaN
df.to_csv(na_rep='\'NA\'')
Out[3]:
",adult,animal,size,weight\n0,False,cat,S,'NA'\n1,False,dog,S,'NA'\n2,False,cat,M,'NA'\n3,False,fish,M,'NA'\n4,False,dog,M,'NA'\n5,True,cat,L,'NA'\n6,True,cat,L,'NA'\n"
EDIT
编辑
To get the desired output use these params:
要获得所需的输出，请使用以下参数：
In [27]:
df.to_csv(na_rep='NA', sep=';', index=False,quoting=3)
?
Out[27]:
'adult;animal;size;weight\nFalse;cat;S;NA\nFalse;dog;S;NA\nFalse;cat;M;NA\nFalse;fish;M;NA\nFalse;dog;M;NA\nTrue;cat;L;NA\nTrue;cat;L;NA\n'
