無效的語法錯誤

-2

我是新來的大熊貓，並在試圖遍歷行通過一個循環我收到的大熊貓無效的語法錯誤

下面以一個無效的語法錯誤是我試圖

for index, row in df.iterrows(): 
if ((df['c1'] == 'cond1')&(df['c2']=='cond2')): 
df['c3']='cond2' 
elif ((df['c1'] == 'cond3')&(df['c2']=='cond2')): 
df['c3']='cond2' 
elif ((df['c1'] == 'cond4')&(df['c2']=='cond2')): 
df['c3']='cond2' 
else: 
df['c3']='Nan' 
df

代碼

來源

2016-09-21 Manasa Murugan

你都清楚地失蹤縮進。請閱讀關於如何在Python中編寫循環和條件的教程。 – sisanared

你也應該粘貼錯誤的回溯。你可以在這裏閱讀縮進： https://docs.python.org/release/2.5.1/ref/indentation.html – noonewin

我認爲你可以使用ix，但是你確定你總是需要字符串cond2轉到列c3？

df['c3']='Nan' 
df.ix[(df['c1'] == 'cond1')&(df['c2']=='cond2'), 'df3'] = 'cond2' 
df.ix[(df['c1'] == 'cond3')&(df['c2']=='cond2'), 'df3'] = 'cond2' 
df.ix[(df['c1'] == 'cond4')&(df['c2']=='cond2'), 'df3'] = 'cond2'

樣品：

import pandas as pd 
import numpy as np 

df = pd.DataFrame({'c1':['cond1','cond2','cond3','cond4'], 
        'c2':['cond2','cond2','cond2','cond2']}) 

print (df) 
     c1  c2 
0 cond1 cond2 
1 cond2 cond2 
2 cond3 cond2 
3 cond4 cond2 

#set to NaN value 
df['c3']= np.nan 
#set to string 'Nan' 
#df['c3']= 'Nan' 

df.ix[(df['c1'] == 'cond1')&(df['c2']=='cond2'), 'c3'] = 'a' 
df.ix[(df['c1'] == 'cond3')&(df['c2']=='cond2'), 'c3'] = 'b' 
df.ix[(df['c1'] == 'cond4')&(df['c2']=='cond2'), 'c3'] = 'c' 
print (df) 
     c1  c2 c3 
0 cond1 cond2 a 
1 cond2 cond2 NaN 
2 cond3 cond2 b 
3 cond4 cond2 c

循環的解決方案是非常緩慢的，但如果需要的話，你需要在循環使用row代替df：

import pandas as pd 
import numpy as np 

df = pd.DataFrame({'c1':['cond1','cond2','cond3','cond4'], 
        'c2':['cond2','cond2','cond2','cond2']}) 

print (df) 

df['c3'] = '' 
for index, row in df.iterrows(): 
    if ((row['c1'] == 'cond1')&(row['c2']=='cond2')): 
     row['c3']='a' 
    elif ((row['c1'] == 'cond3')&(row['c2']=='cond2')): 
     row['c3']='b' 
    elif ((row['c1'] == 'cond4')&(row['c2']=='cond2')): 
     row['c3']='c' 
    else: 
     row['c3']=np.nan 

print (df) 
     c1  c2 c3 
0 cond1 cond2 a 
1 cond2 cond2 NaN 
2 cond3 cond2 b 
3 cond4 cond2 c

來源

2016-09-21 07:43:48 jezrael

這段代碼可能會讓一些正在學習用Python編寫代碼的人感到困惑。 – sisanared

無效的語法錯誤

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