I have a pandas DataFrame 'df' with x rows, and another pandas DataFrame 'df2' with y rows
(x < y). I want to return the indexes of where the values of df['Farm'] equals the value of df2['Fields'], in order to add respective 'Manager' to df.
the code I have is as follows:
data2 = [['field1', 'Paul G'] , ['field2', 'Mark R'], ['field3', 'Roy Jr']]
data = [['field1'] , ['field2']]
columns = ['Field']
columns2 = ['Field', 'Manager']
df = pd.DataFrame(data, columns=columns)
df2 = pd.DataFrame(data2, columns=columns2)
farmNames = df['Farm']
exists = farmNames.reset_index(drop=True) == df1['Field'].reset_index(drop=True)
This returns the error message:
ValueError: Can only compare identically-labeled Series objects
Does anyone know how to fix this?
As #NickODell mentioned, you could use a merge, basically a left join. See below code.
df_new = pd.merge(df, df2, on = 'Field', how = 'left')
print(df_new)
Output:
Field Manager
0 field1 Paul G
1 field2 Mark R
Related
If I need to map one value between two dataframes, and get 'FD' value from row where Round = 1 an Id is 262:
df1 = pd.DataFrame({'Round':1,'ID':262,'FD':30,
'Round':2,'ID':262,'FD':20}, index=[0])
df2 = pd.DataFrame({'Round':1, 'Opponent':262,
'Round':2, 'Opponent':262},index=[0])
I have tried to map with:
df2['P_GS_by_FD'] = f2['Opponent'].map(df1.set_index('ID')['FD'])
df2 Expected output:
Round Opponent P_GS_by_FD
1 262 30
I would use drop_duplicates
this would select 'Round 1' rows
df1.drop_duplicates('Id', keep='first')
df2['P_GS_by_FD'] = df2['Opponent'].map(df1.drop_duplicates('Id', keep='first').set_index('Id')['FD'])
(I think your example df1, df2 would make only one row instead of two)
Then we need create the round in df2 as well
df2['Round'] = df.groupby('Opponent').cumcount()+1
yourdf = df2.merge(df1.rename(columns={'Id' : 'Opponent'}), on = ['Opponent','Round'], how = 'left')
Base on your update
yourdf = df2.merge(df1.rename(columns={'ID' : 'Opponent'}), on = ['Opponent','Round'], how = 'left')
i have two parquet files, which i load with spark.read. These 2 dataframes have a same column named key, so i join them with:
df = df.join(df2, on=['key'], how='inner')
df columns are: ["key","Duration","Distance"] and df2 : ["key",department id"]. At the end i want to print Duration, max(Distance),department id group by department id. What i have done so far is:
df.join(df.groupBy('departmentid').agg(F.max('Distance').alias('Distance')),on='Distance',how='leftsemi').show()
but i think it is too slow, is there a faster way to achieve my goal?
thanks in advance
EDIT: sample (first 2 lines of each file)
df:
369367789289,2015-03-27 18:29:39,2015-03-27 19:08:28,-
73.975051879882813,40.760562896728516,-
73.847900390625,40.732685089111328,34.8
369367789290,2015-03-27 18:29:40,2015-03-27 18:38:35,-
73.988876342773438,40.77423095703125,-
73.985160827636719,40.763439178466797,11.16
df1:
369367789289,1
369367789290,2
each columns is seperated by "," first column on both files is my key, then i have timestamps,longtitudes and latitudes. At the second file i have only the key and department id.
to create Distance i am using a function called formater. this is how i get my distance and duration:
df = df.filter("_c3!=0 and _c4!=0 and _c5!=0 and _c6!=0")
df = df.withColumn("_c0", df["_c0"].cast(LongType()))
df = df.withColumn("_c1", df["_c1"].cast(TimestampType()))
df = df.withColumn("_c2", df["_c2"].cast(TimestampType()))
df = df.withColumn("_c3", df["_c3"].cast(DoubleType()))
df = df.withColumn("_c4", df["_c4"].cast(DoubleType()))
df = df.withColumn("_c5", df["_c5"].cast(DoubleType()))
df = df.withColumn("_c6", df["_c6"].cast(DoubleType()))
df = df.withColumn('Distance', formater(df._c3,df._c5,df._c4,df._c6))
df = df.withColumn('Duration', F.unix_timestamp(df._c2) -F.unix_timestamp(df._c1))
and then as i showed above:
df = df.join(vendors, on=['key'], how='inner')
df.registerTempTable("taxi")
df.join(df.groupBy('vendor').agg(F.max('Distance').alias('Distance')),on='Distance',how='leftsemi').show()
Output must be
Distance Duration department id
grouped by id, and geting only the row with max(distance)
Good day SO community,
I have been having an issue with trying to highlight errors in my df, row by row.
reference_dict = {'jobclass' : ['A','B'], 'Jobs' : ['Teacher','Plumber']}
dict = {'jobclass': ['A','C','A'], 'Jobs': ['Teacher', 'Plumber','Policeman']}
df = pd.DataFrame(data=dict)
def highlight_rows(df):
for i in df.index:
if df.jobclass[i] in reference_dict['jobclass']:
print(df.jobclass[i])
return 'background-color: green'
df.style.apply(highlight_rows, axis = 1)
I am getting the error:
TypeError: ('string indices must be integers', 'occurred at index 0')
What i hope to get is my df with values not found in my reference_dict being highlighted.
Any help would be greatly appreciated.. Cheers!
Edit:
x = {'jobclass' : ['A','B'], 'Jobs' : ['Teacher','Plumber']}
d = {'jobclass': ['A','C','A'], 'Jobs': ['Teacher', 'Plumber','Policeman']}
df = pd.DataFrame(data=d)
print(df)
def highlight_rows(s):
ret = ["" for i in s.index]
for i in df.index:
if df.jobclass[i] not in x['jobclass']:
ret[s.index.get_loc('Jobs')] = "background-color: yellow"
return ret
df.style.apply(highlight_rows, axis = 1)
Tried this and got the whole column highlighted instead of the specific rows values that i desire.. =/
You can use merge with parameter indicator for found not matched values and then create DataFrame of styles:
x = {'jobclass' : ['A','B'], 'Jobs' : ['Teacher','Plumber']}
d = {'jobclass': ['A','C','A'], 'Jobs': ['Teacher', 'Plumber','Policeman']}
df = pd.DataFrame(data=d)
print (df)
jobclass Jobs
0 A Teacher
1 C Plumber
2 A Policeman
Detail:
print (df.merge(pd.DataFrame(x) , on='jobclass', how='left', indicator=True))
jobclass Jobs_x Jobs_y _merge
0 A Teacher Teacher both
1 C Plumber NaN left_only
2 A Policeman Teacher both
def highlight_rows(s):
c1 = 'background-color: yellow'
c2 = ''
df1 = pd.DataFrame(x)
m = s.merge(df1, on='jobclass', how='left', indicator=True)['_merge'] == 'left_only'
df2 = pd.DataFrame(c2, index=s.index, columns=s.columns)
df2.loc[m, 'Jobs'] = c1
return df2
df.style.apply(highlight_rows, axis = None)
Good day to you as well!
What i hope to get is my df with values not found in my reference_dict being highlighted.
If you're looking for values not found in reference_dict to be highlighted, do you mean for the function to be the following?
def highlight_rows(df):
for i in df.index:
if df.jobclass[i] not in reference_dict['jobclass']:
print(df.jobclass[i])
return 'background-color: green'
Either way, why highlight the rows when you could isolate them? It seems like you want to look at all of the job classes in df where there is not one in reference_dict.
import pandas as pd
reference_dict = {'jobclass' : ['A','B'], 'Jobs' : ['Teacher','Plumber']}
data_dict = {'jobclass': ['A','C','A'], 'Jobs': ['Teacher', 'Plumber','Policeman']}
ref_df = pd.DataFrame(reference_dict)
df = pd.DataFrame(data_dict)
outliers = df.merge(ref_df, how='outer', on='jobclass') # merge the two tables together, how='outer' includes jobclasses which the DataFrames do not have in common. Will automatically generate columns Jobs_x and Jobs_y once joined together because the columns have the same name
outliers = outliers[ outliers['Jobs_y'].isnull() ] # Jobs_y is null when there is no matching jobclass in the reference DataFrame, so we can take advantage of that by filtering
outliers = outliers.drop('Jobs_y', axis=1) # let's drop the junk column after we used it to filter for what we wanted
print("The reference DataFrame is:")
print(ref_df,'\n')
print("The input DataFrame is:")
print(df,'\n')
print("The result is a list of all the jobclasses not in the reference DataFrame and what job is with it:")
print(outliers)
The result is:
The reference DataFrame is:
jobclass Jobs
0 A Teacher
1 B Plumber
The input DataFrame is:
jobclass Jobs
0 A Teacher
1 C Plumber
2 A Policeman
The result is a list of all the jobclasses not in the reference DataFrame and what job is with it:
jobclass Jobs_x
2 C Plumber
This could have been a tangent but it's what I'd do. I was not aware you could highlight rows in pandas at all, cool trick.
I have two dataframes both of which have the same basic schema. (4 date fields, a couple of string fields, and 4-5 float fields). Call them df1 and df2.
What I want to do is basically get a "diff" of the two - where I get back all rows that are not shared between the two dataframes (not in the set intersection). Note, the two dataframes need not be the same length.
I tried using pandas.merge(how='outer') but I was not sure what column to pass in as the 'key' as there really isn't one and the various combinations I tried were not working. It is possible that df1 or df2 has two (or more) rows that are identical.
What is a good way to do this in pandas/Python?
Try this:
diff_df = pd.merge(df1, df2, how='outer', indicator='Exist')
diff_df = diff_df.loc[diff_df['Exist'] != 'both']
You will have a dataframe of all rows that don't exist on both df1 and df2.
IIUC:
You can use pd.Index.symmetric_difference
pd.concat([df1, df2]).loc[
df1.index.symmetric_difference(df2.index)
]
You can use this function, the output is an ordered dict of 6 dataframes which you can write to excel for further analysis.
'df1' and 'df2' refers to your input dataframes.
'uid' refers to the column or combination of columns that make up the unique key. (i.e. 'Fruits')
'dedupe' (default=True) drops duplicates in df1 and df2. (refer to Step 4 in comments)
'labels' (default = ('df1','df2')) allows you to name the input dataframes. If a unique key exists in both dataframes, but have
different values in one or more columns, it is usually important to know these rows, put them one on top of the other and label the row with the name so we know to which dataframe does it belong to.
'drop' can take a list of columns to be excluded from the consideration when considering the difference
Here goes:
df1 = pd.DataFrame([['apple', '1'], ['banana', 2], ['coconut',3]], columns=['Fruits','Quantity'])
df2 = pd.DataFrame([['apple', '1'], ['banana', 3], ['durian',4]], columns=['Fruits','Quantity'])
dict1 = diff_func(df1, df2, 'Fruits')
In [10]: dict1['df1_only']:
Out[10]:
Fruits Quantity
1 coconut 3
In [11]: dict1['df2_only']:
Out[11]:
Fruits Quantity
3 durian 4
In [12]: dict1['Diff']:
Out[12]:
Fruits Quantity df1 or df2
0 banana 2 df1
1 banana 3 df2
In [13]: dict1['Merge']:
Out[13]:
Fruits Quantity
0 apple 1
Here is the code:
import pandas as pd
from collections import OrderedDict as od
def diff_func(df1, df2, uid, dedupe=True, labels=('df1', 'df2'), drop=[]):
dict_df = {labels[0]: df1, labels[1]: df2}
col1 = df1.columns.values.tolist()
col2 = df2.columns.values.tolist()
# There could be columns known to be different, hence allow user to pass this as a list to be dropped.
if drop:
print ('Ignoring columns {} in comparison.'.format(', '.join(drop)))
col1 = list(filter(lambda x: x not in drop, col1))
col2 = list(filter(lambda x: x not in drop, col2))
df1 = df1[col1]
df2 = df2[col2]
# Step 1 - Check if no. of columns are the same:
len_lr = len(col1), len(col2)
assert len_lr[0]==len_lr[1], \
'Cannot compare frames with different number of columns: {}.'.format(len_lr)
# Step 2a - Check if the set of column headers are the same
# (order doesnt matter)
assert set(col1)==set(col2), \
'Left column headers are different from right column headers.' \
+'\n Left orphans: {}'.format(list(set(col1)-set(col2))) \
+'\n Right orphans: {}'.format(list(set(col2)-set(col1)))
# Step 2b - Check if the column headers are in the same order
if col1 != col2:
print ('[Note] Reordering right Dataframe...')
df2 = df2[col1]
# Step 3 - Check datatype are the same [Order is important]
if set((df1.dtypes == df2.dtypes).tolist()) - {True}:
print ('dtypes are not the same.')
df_dtypes = pd.DataFrame({labels[0]:df1.dtypes,labels[1]:df2.dtypes,'Diff':(df1.dtypes == df2.dtypes)})
df_dtypes = df_dtypes[df_dtypes['Diff']==False][[labels[0],labels[1],'Diff']]
print (df_dtypes)
else:
print ('DataType check: Passed')
# Step 4 - Check for duplicate rows
if dedupe:
for key, df in dict_df.items():
if df.shape[0] != df.drop_duplicates().shape[0]:
print(key + ': Duplicates exists, they will be dropped.')
dict_df[key] = df.drop_duplicates()
# Step 5 - Check for duplicate uids.
if type(uid)==str or type(uid)==list:
print ('Uniqueness check: {}'.format(uid))
for key, df in dict_df.items():
count_uid = df.shape[0]
count_uid_unique = df[uid].drop_duplicates().shape[0]
var = [0,1][count_uid_unique == df.shape[0]] #<-- Round off to the nearest integer if it is 100%
pct = round(100*count_uid_unique/df.shape[0], var)
print ('{}: {} out of {} are unique ({}%).'.format(key, count_uid_unique, count_uid, pct))
# Checks complete, begin merge. '''Remenber to dedupe, provide labels for common_no_match'''
dict_result = od()
df_merge = pd.merge(df1, df2, on=col1, how='inner')
if not df_merge.shape[0]:
print ('Error: Merged DataFrame is empty.')
else:
dict_result[labels[0]] = df1
dict_result[labels[1]] = df2
dict_result['Merge'] = df_merge
if type(uid)==str:
uid = [uid]
if type(uid)==list:
df1_only = df1.append(df_merge).reset_index(drop=True)
df1_only['Duplicated']=df1_only.duplicated(keep=False) #keep=False, marks all duplicates as True
df1_only = df1_only[df1_only['Duplicated']==False]
df2_only = df2.append(df_merge).reset_index(drop=True)
df2_only['Duplicated']=df2_only.duplicated(keep=False)
df2_only = df2_only[df2_only['Duplicated']==False]
label = labels[0]+' or '+labels[1]
df_lc = df1_only.copy()
df_lc[label] = labels[0]
df_rc = df2_only.copy()
df_rc[label] = labels[1]
df_c = df_lc.append(df_rc).reset_index(drop=True)
df_c['Duplicated'] = df_c.duplicated(subset=uid, keep=False)
df_c1 = df_c[df_c['Duplicated']==True]
df_c1 = df_c1.drop('Duplicated', axis=1)
df_uc = df_c[df_c['Duplicated']==False]
df_uc_left = df_uc[df_uc[label]==labels[0]]
df_uc_right = df_uc[df_uc[label]==labels[1]]
dict_result[labels[0]+'_only'] = df_uc_left.drop(['Duplicated', label], axis=1)
dict_result[labels[1]+'_only'] = df_uc_right.drop(['Duplicated', label], axis=1)
dict_result['Diff'] = df_c1.sort_values(uid).reset_index(drop=True)
return dict_result
Set df2.columns = df1.columns
Now, set every column as the index: df1 = df1.set_index(df1.columns.tolist()), and similarly for df2.
You can now do df1.index.difference(df2.index), and df2.index.difference(df1.index), and the two results are your distinct columns.
with
left_df.merge(df,left_on=left_df.columns.tolist(),right_on=df.columns.tolist(),how='outer')
you can get the outer join result.
Similarly, you can get the inner join result.Then make a diff that would be what you want.
I am really struggling to make it work...
How can I get a Series, transform it to a dataframe, add a column to it, and concatenate it in a loop?
The pseudo code is below, but the correct syntax is a mystery to me:
The Pseudo code is:
def func_B_Column(df):
return 1
df_1 = (...) # columns=['a', 'etc1', 'etc2']
df_2 = pandas.DataFrame(columns=['a','b','c'])
listOfColumnC = ['c1','c2','c3']
for var in listOfColumnC :
series = df_1.groupby('a').apply(func_B_Column) #series object should have now 'a' as index, and func_B_Column as value
aux = series.to_frame('b')
aux['c'] = aux.apply(lambda x: var, axis=1) #add another column 'c' to the series object
df_2 = df_2 .append(aux) #concatenate the results as rows, at the end
Edited after the question's refinement
df_2 = DataFrame()
for var in listOfColumnC :
df_2 = df_2.append(DataFrame({'b': df_1.groupby('a').apply(func_B_Column), 'c': var}))