CODEWITHSUNDEEP
pythonfunctionpandas
Joseph0210
Joseph0210

Reputation: 195

function that takes one column value and returns another column value

Apologies, if this is a duplicate please let me know, I'll gladly delete.

My dataset: 

Index     Col 1      Col 2

0         1       4, 5, 6   
1         2       7, 8, 9
2         3       10, 11, 12   
3         4       13, 14, 15

I am attempting to create a function that will take a particular column 1 value as its input and output the column 1 value with its corresponding column 2 values.

For example, if I used the function for when column 1 is equal to 3, the function would return a list of 4 values: 3, 10, 11, 12

Many thanks

Upvotes: 0

Views: 1013

Answers (2)

jezrael
jezrael

Reputation: 862641

def f(a):
    return df.loc[df['Col 1'] == a, 'Col 2'].item()

But if need more general:

print (df)
   Col 1       Col 2
0      1     4, 5, 6
1      1     7, 8, 9
2      3  10, 11, 12
3      4  13, 14, 15

def f(a):
    a = df.loc[df['Col 1'] == a, 'Col 2']
    #for no match
    if a.empty:
        return 'no match'
    #for multiple match
    elif len(a) > 1:
        return a
    else:
    #for match one value only
        return a.item()

print (f(1))
0    4, 5, 6
1    7, 8, 9
Name: Col 2, dtype: object

print (f(3))
10, 11, 12

print (f(6))
no match

Upvotes: 4

cmdLP
cmdLP

Reputation: 1856

Just a simple function:

def getColumn(col1):
    beg = 1+3*col1
    return [col1] + list(range(beg, beg+3))

Upvotes: 0

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